The 97 PCM is indeed the same mix as the 91 LD. I do think there was some slight processing done, as it seemed like it peaked more and that it was slightly less detailed than the 91 version.
The 97 overall is an improvement of the same transfer. Pressing done by Pioneer, THX certified disc-but there seems to be a slight amount of DVNR and a touch of smearing occasionally.
I prefer the 91 disc overall. Kinda feels like the film a little more.