https://www.youtube.com/watch?v=GO3ARNNSfKk&feature=youtu.be
No mention whatsoever that it was Watchtower themselves that strongly hinted towards this date. Instead they blame those who "put their trust in a date, not Jehovah".
Let's recap...
"Does God's rest day parallel the time man has been on earth since his
creation? Apparently so.
In what year, then, would the first 6,000 years of man's existence
and also the first 6,000 years of Gods rest day come to an end?
The year 1975.
It means that within a relatively few years we will witness the fulfilment of the remaining prophecies
that have to do with the "time of the end"." Awake! 1966 Oct 8 pp.19-20
"It did not take the brothers very long to find the chart beginning on page 31,
showing that 6,000 years of man's existence end in 1975. Discussion of 1975 overshadowed about everything else.
"The new book compels us to realize that Armageddon is, in fact,
very close indeed," said a conventioner. Surely it was one of the
outstanding blessings to be carried home!" .. Brother Franz. 'Does it mean that Armageddon is going to be finished, with Satan bound, by 1975? It could! It could!
All things are possible with God. Does it mean that Babylon
the Great is going to go down by 1975? It could. Does it mean that the
attack of Gog of Magog is going to be made on Jehovah's witnesses to
wipe them out, then Gog himself will be put out of action? It could. But
we are not saying. All things are possible with God. But we are not saying. And don't any of you be specific in saying anything that is going to happen between now and 1975.
But the big point of it all is this, dear friends: Time is short. Time is running out, no question about that."
Watchtower 1966 Oct 15 pp.629,631
"Well now, as Jehovah's Witnesses, as runners, even though some of us
have become a little weary, it almost seems as though Jehovah has
provided meat in due season. Because he's held up before all of us, a
new goal. A new year. Something to reach out for and it just seems it
has given all of us so much more energy and power in this final burst of
speed to the finish line. And that's the year 1975. Well, we don't have
to guess what the year 1975 means if we read the Watchtower. And don't
wait 'till 1975. The door is going to be shut before then. As one
brother put it, "Stay alive to Seventy-Five""
- 1967 District Convention, Wisconsin Sheboygan District Overseer Brother Charles Sunutko
"The immediate future is certain to be filled with climactic events, for this old system is nearing its complete end.
Within a few years at most the final parts of Bible prophecy relative to these "last days" will undergo fulfillment."
Watchtower 1968 May 1 p.272

"With the appearance of the book Life Everlasting-in Freedom of the Sons of God,
and its comments as to how appropriate it would be for the millennial
reign of Christ to parallel the seventh millennium of man's existence, considerable expectation was aroused regarding the year 1975. ... Unfortunately, however, along with such cautionary information, there
were other statements published that implied that such realization of
hopes by that year was more of a probability than a mere possibility
." Watchtower 1980 Mar 15 p.17
I rest my case m'lord.