Is there maybe a possibility that they also presented a new 70mm cut of Empire with a slightly new mix when it was re-released the following years after its premiere when the 35mm cut had in a way already taken the place as the final cut? Or was it the same prints with the same "unfinished shots" that was also presented in '81, '82 or even later...?
A poster advertising a special 70mm screening of the trilogy back in 1985, lucky bastards who saw it! ;)