A few excerpts, but I don't know if they meet your criteria. If you include "prophet" in quotes, there are quite a few more. Can't format it too well - using a tablet.
WT 1919 Oct 1 p.297 - "This was the test - the coming down of fire; and the fulfilment exactly on time has proved that Pastor Russell was one of God's great reformers and prophets."
w59 1/15 pp. 40-41 pars. 11-14 Down with the Old—Up with the New! -
11 Jeremiah prophesied forty years in the time of the end of the kingdom of Judah. So who will prophesy with his message in this time of the end of the nations of this world?
13 The fact that decides the answer to the question is, not, Do all the clergy of Roman Catholicism and of Protestantism agree that Jehovah's witnesses have been and are God's prophet to the nations? but, Who discerned the divine will for Christians in this time of the world's end and offered themselves to do it? Who have undertaken God's foreordained work for this day of judgment of the nations? Who have answered the call to the work and have done it down till this year 1958? Whom has God actually used as his prophet?
14 By the historical facts of the case Christendom is beaten back in defeat. Jehovah's witnesses are deeply grateful today that the plain facts show that God has been pleased to use them. All the preaching and all the Bible educational work that they have done till now in 175 countries and islands of the sea they confess has been, not by help of a military army, nor by human power, but by God's spirit, his invisible active force. (Zech. 4:6, AV) It has been because Jehovah thrust out his hand of power and touched their lips and put his words in their mouths.
Awake 6/8/1986 p.9 - "You will be interested to learn that God has on earth a people, all of whom are prophets, or witnesses for God. In fact, they are known throughout the world as Jehovah's Witnesses."
Reasoning From the Scriptures (1989) p.133 - "If any individual claim to represent God but decline to use god's personal name, and make it a practice to express their own opinions on matters, are they measuring up to this important qualification of a true prophet?"
w91 9/1 p. 29 par. 20 - By our preaching and by our very presence, we are warning the wicked. (Ezekiel 33:33) ["And when it comes true—look! it must come true—they will also have to know that a prophet himself had proved to be in the midst of them]
w99 10/1 5 "For Everything There Is an Appointed Time" - "For the Sovereign Lord Jehovah will not do a thing unless he has revealed his confidential matter to his servants the prophets." (Amos 3:7) ... For that purpose God has authorized a "faithful and discreet slave"to provide his people with "their [spiritual] food at the proper time."
w10 7/15 p. 11 par. 18 "What Sort of Persons Ought You to Be!" - "At the same time, Jehovah will honor his faithful servants by making it abundantly clear that they were, indeed, his representatives.—Read Ezekiel 2:5; 33:33."
(Eze 2:5) And as for them, whether they will hear or will refrain—for they are a rebellious house—they will certainly know also that a prophet himself happened to be in the midst of them.
(Eze 33:33) And when it comes true—look! it must come true—they will also have to know that a prophet himself had proved to be in the midst of them."
w14 11/15 p. 30 11 - "Revelation 11:3 speaks of two witnesses who would prophesy for 1,260 days... However, true to the words of the prophecy, at the end of the three and a half days, the two witnesses were brought back to life. Not only were these anointed ones released from prison but those who remained faithful received a special appointment from God through their Lord, Jesus Christ. In 1919 they were among those who were appointed to serve as a "faithful and discreet slave" to care for the spiritual needs of God’s people during the last days."
