Some 5 years after the embarrassing date of 1975, Watchtower did an about-face with a semi-apology -- noting that "published [by Watchtower] statements that implied that such realization of hopes by that year was more of a probability than a mere possiblity. It is to be regretted ..."
Note the passive voice "it is to be regretted" instead of the active voice "we regret". The weak passive voice apology is about as strong as we'll ever hear from Watchtower.
. . . considerable expectation was aroused regarding the year 1975. There were statements made then, and thereafter, stressing that this was only a possibility. 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. It is to be regretted that these latter statements apparently overshadowed the cautionary ones and contributed to a buildup of the expectation already initiated. WT Mar 15, 1980 p 17
Therefore, in my opinion, Watchtower took the year 1975 off the table 43 years ago.