At present there is only evidence to suggest that it been used five times in that comeback Vegas run - on 23 Aug DS, on 24 Aug MS, both shows on the 25th and at the Dinner Show on the 26th.
One of the first things that we heard in the original TTWII movie, during Culver City rehearsals, was that he was unhappy with the arrangement, the ending in particular and this would possibly explain it's limited use in August 69 and it's complete disappearance for the next engagement. Whether it was brought back because they thought they had fixed the problem or that it was performed purely for the MGM cameras is pure conjecture as he only sang it twice in August 70, on opening night and this performance from the Midnight Show on 12 August and then apparantly dropped it completely.
Despite filming both versions in August, neither made it into the final cut of either the 1970 or 2001 versions of the movie although both films contain rehearsal sequences of the song. The latter movie used 'Words' as a link to advance the movie from the International's Convention Room rehearsals to the stage rehearsals by switching half way through the song.
This live performance was first heard on Disc #2 of the 2001 TTWII special edition CD boxset amongst the entire show from 12 August Midnight Show. The original audio in this video has been replaced by audio taken from disc #6 of Sony's excellent TTWII Deluxe Edition which contains that 12 August 1970 midnight show.