Just got this response from the head projectionist:
I can answer a few of the film questions for you. It is a 1992 Eastman LPP print, good eye. It is also a Dolby Stereo print. We played it in SR which would have done some 2:4 sound matrixing using the equivalent of Pro-Logic. This print came straight from the Warner Brothers archives.
That would explain the cleanliness.