Something that gets lost in the debate over whether the WTS ever claimed in print that Armageddon would come in 1975 is that they did teach, in print, that 1975 would be the end of 6,000 years of man's existance on earth.
What significance is that? According to the WTS, in print, Jesus would start his new 1,000 year reign of peace at the start of the new "millenium". Satan would be abyssed, war will end, the wicked destroyed.
Whether the WTS said in so many words, "Armageddon is coming in 1975" or not, it is strongly associated with the then coming 1,000 year period of peace and rule by Jesus.
Does the WTS still teach this 1,000 year stuff?
Taken from the booklet, "The Approaching Peace of a Thousand Years" released in 1969:
More recently earnest researchers of the Holy Bible have made a recheck of its chronology. According to their calculations the six millenniums of mankind's life on earth would end in the mid-seventies. Thus the seventh millennium from man's creation by Jehovah God would begin within less than ten years.*
Apart from the global change that present-day world conditions indicate is fast getting near, the arrival of the seventh millennium of man's existence on earth suggests a gladsome change for war-stricken humankind. According to the first two chapters of the Holy Bible man and woman were created toward the close of the sixth creative day. We are now living in the seventh creative day, and on this seventh day Jehovah God has been resting from earthly creation. To run parallel with this resting of God on his seventh creative day, he gave the Ten Commandments to his prophet Moses, in the fourth one of which God commanded that his chosen people should rest on the seventh day of the week. (Exodus 20:8-11) That day was therefore the weekly sabbath day, the day of desistance from human toil.* See the book Aid to Bible Understanding , page 333, under "Chronology." Also, the book Life Everlasting — in Freedom of the Sons of God , pages 26-35, under the subheading "Six Thousand Years of Human Existence Closing," published in 1966.
The Lord Jesus Christ, the prospective Prince of Peace, pointed forward to a greater Sabbath Day. Pointing forward to this, he said on a certain weekly sabbath day when he came under criticism: "Lord of the sabbath is what the Son of man is." (Matthew 12:1-8) He was referring to his peaceful reign of a thousand years. Jehovah God measures human affairs according to a thousand-year-length rule. He inspired the prophet Moses to write, in Psalm 90:4: "A thousand years are in your eyes but as yesterday when it is past." He also inspired the Christian apostle Peter to write: "One day is with the Lord as a thousand years, and a thousand years as one day." (2 Peter 3:8, AV ) In prophetic vision the apostle John saw Satan the Devil and his demons bound and abyssed for a thousand years, during which thousand years Jesus Christ reigned with his victorious disciples over all mankind. (Revelation 5:9, 10; 20:1-7) So, according to God's viewpoint of time, that thousand years of his Son Jesus Christ would correspond with merely "one day."
In order for the Lord Jesus Christ to be "Lord even of the sabbath day," his thousand-year reign would have to be the seventh in a series of thousand-year periods or millenniums. (Matthew 12:8, AV ) Thus it would be a sabbatic reign. Since early in the existence of mankind Satan the Devil has been on the loose, making the human family to toil in hard bondage, causing the earth to be filled with violence before the global flood of Noah's day and inducing the same old earth to be filled with even greater violence today. Soon now six millenniums of his wicked exploiting of mankind as his slaves will end, within the lifetime of the generation that has witnessed world events since the close of the Gentile Times in 1914 till now, according to the prophetic words of Jesus in Matthew 24:34. Would not, then, the end of six millenniums of mankind's laborious enslavement under Satan the Devil be the fitting time for Jehovah God to usher in a Sabbath millennium for all his human creatures? Yes, indeed! And his King Jesus Christ will be Lord of that Sabbath.In ancient times, when God's chosen people were under the Ten Commandments given through his prophet Moses, the weekly sabbath was a peaceful day. To agree with God's own desistance from earthly work on his seventh creative day, his people were under divine command to desist from the hard work of the preceding six days, likewise their domestic animals. (Exodus 20:1-11) In like manner Christ's sabbatic reign for a thousand years will be a peaceful time for this earth and its inhabitants. It will be a time of rest from all the warfare and violence of the previous six millenniums. Swords, symbolic of murderous warfare, will have been beaten into plowshares, and spears into pruning hooks for the grapevines. Life will not be dull in that restful millennial sabbath. It will not be a time of idleness. The Sabbath Lord, Jesus Christ the King, will not be idle, neither will he let his earthly subjects be idle.
Why was it that Jesus Christ, when on earth as a Jew under the Ten Commandments, did so many of his miraculous works on the weekly sabbath day, healing the sick and the crippled? Not only to show that it was right to do good on the sabbath. It was also to foreshadow how, during his sabbatic reign, he will deliver humankind from bondage to Satan the Devil and his demons and relieve them of the deadly effects of the sin and imperfection inherited from our first human parents, Adam and Eve. War and violence during the past six millenniums have brought millions of humans to untimely death and the grave; but the Lord of the Sabbath, Jesus Christ, will bring up the thousands of millions of dead humankind from the graves, exactly as he prophesied that he would do. (John 5:28, 29) It was no mere idle phrase when his truthful apostle Paul wrote that God's sabbath law had a "shadow of the good things to come." — Hebrews 10:1; Colossians 2:16, 17.