The Watchtower Society puts out two (or more) views on nearly all of their controversial teachings. That way they can emphasize the one view to their members (i.e.: If you leave the Watchtower Organization you will be destroyed), but they can also show the other view to outsiders in order to look more mainstream, more like a regular non-cult religion (i.e.: Other people may be saved, it is up to God, not us, to judge).
Here is a quote from their brochure from 2000 called "Jehovah's Witnesses -- Who Are They? What Do They Believe?", Page 29:
"Do they believe that they are the only ones who will be saved?
No. Millions that have lived in centuries past and who were not Jehovah’s Witnesses will come back in a resurrection and have an opportunity for life. Many now living may yet take a stand for truth and righteousness before the “great tribulation,” and they will gain salvation. Moreover, Jesus said that we should not be judging one another. We look at the outward appearance; God looks at the heart. He sees accurately and judges mercifully. He has committed judgment into Jesus’ hands, not ours.—-Matthew 7:1-5; 24:21; 25:31."
Compare that quote with this quote:
"Our Kingdom Ministry", November 1972, Page 8:
"The Bible makes plain that it is only those calling on “the name of Jehovah” who will be saved. But, “how will they call on him in whom they have not put faith? How, in turn, will they put faith in him of whom they have not heard? How, in turn, will they hear without someone to preach?”-—Rom. 10:13, 14."
Here are some more quotes which say that ONLY Jehovah's Witnesses will be saved:
The Watchtower, February 1, 1981 Issue, Pages 23-24:
"However, is it only those who claim to be Christian who are facing the threat of destruction at the end of this system of things? No, but all other religionists are, also those who refuse to join any part of organized religion. Earth’s Creator, Jehovah God, knows this. He would rather not destroy the world of mankind. His prime desire is that as many of them as possible should be saved from eternal destruction and should prove worthy of life in his righteous new system of things. In that behalf he has had his warning sounded out far and wide.
13 Mercifully he notified first the “slave” class, as pictured by Ezekiel. Thus he made this class his composite “watchman.” This “watchman” class is especially charged with sounding the divine warning. Because of their timely warning more and more people are being enabled to hear and to act upon what they hear, with hope of being spared clear through the old world’s end. As for those refusing to heed the God-given warning, their blood will be upon their own heads."
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The Watchtower, November 1, 1997 Issue, Page 7:
"Would you like to live in such a world? Only those who adhere to God’s requirements will do so, and his requirements are clearly set out in the Bible. (John 17:3; Acts 2:38-42) Jehovah’s Witnesses will be happy to help you to learn what God requires so that you can hope to enjoy life forever in a truly united world."
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The Watchtower, August 1, 1992 Issue, Page 30:
"The best place to be during the stormy times that lie ahead is within Jehovah’s organization, safe under his protection. Only those who take refuge in Jehovah have a firm hope of being hidden from his wrath on the great day of his anger.—-Zephaniah 2:2, 3."
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The Watchtower, March 1, 1991 Issue, Page 7:
"This coming expression of God’s anger, which the Bible calls Armageddon, will unquestionably demonstrate that he does indeed exist. Only those who accept his sovereignty will survive that event."
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The Watchtower, February 1, 1987 Issue, Page 11:
"How would you react if you knew that many people, including some who were close to you, would soon perish in that tribulation? Would you be eager to help? Recall Ezekiel’s prophetic vision of the man with the secretary’s inkhorn. He was told that only those who had received the symbolic mark on their forehead would survive the destruction of Jerusalem, and he was the one to administer that lifesaving mark. How did he respond? “I have done just as you have commanded me,” he reported.—Ezekiel 9:1-11.
Are you manifesting the same willingness and eagerness as the man clothed with linen, doing just as Jehovah has commanded? What has Jehovah commanded? Through his Son, Jesus Christ, he has given the order: “Go therefore and make disciples of people of all the nations, . . . teaching them to observe all the things I have commanded you.” (Matthew 28:19, 20) This is as much a lifesaving work as the symbolic marking of the foreheads in Ezekiel’s day. Anyone who does not respond and become a disciple of Jesus Christ will suffer destruction at the hand of God’s Chief Executioner. (2 Thessalonians 1:6-8) Do you sense the urgency? Do you show it by manifesting an eagerness to declare the good news?"
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The Watchtower, December 15, 1987 Issue, Page 7:
"Being at the “corners” of the earth, the angels are in position to loose destructive “winds” from all directions. No area of the earth will be spared, which will mean “harm,” or destruction, for this wicked system and all its supporters. God’s angels are thus described as ready to go into action when the signal is given!-—Revelation 7:3; 19:11-21.
The destructive “harm,” though, is to be on only those who do not respond to the angelically backed message now being preached earth wide. It will not harm those who are searching for God and who listen to the Kingdom message. They will be preserved, as God’s Word says: “Seek Jehovah, all you meek ones of the earth . . . Seek righteousness, seek meekness. Probably you may be concealed in the day of Jehovah’s anger.”-—Zephaniah 2:3. [...]
So, then, the question you need to ask is: ‘What will be my future?’ The answer depends on how you react to angelic direction. Will you listen and respond when you are presented with the message that they are backing? If you do, you will be among those who can look forward with confidence to the future, having God’s sure promise: “The world is passing away and so is its desire, but he that does the will of God remains forever.”—-1 John 2:17."
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The Watchtower, March 1, 1984 Issue, Page 8:
"Only those who, as worshipers of Jehovah, have heeded his counsel to “seek peace and pursue it” will be delivered during the great tribulation that will then engulf mankind.—-1 Peter 3:11; Revelation 17:1, 2, 16; 18:24."