In short;

Criterion had SK and his editor on Full Metal Jacket approve the transfer of a 35mm intermediate negative and it was timed to their specifications. There may have been some slight cropping for TVs and machines of the time but most 35mm prints were already hard cropped to 2.21:1. The sound is the 70mm 6 track mag stereo run through a Dolby matrix encoder.

(This info copied from disc insert.)

MGM's first disc a few years later used 70mm sources but has totally different color, without the browns and 60's look that is found only on print sources and the Criterion. Later for the CAV box they re-timed the same master and made it better. The last version added an ac3 track and this was ported to DVD, and I'll try to find one. The caps from DVDBeaver show that perhaps it is too far on the brown side and that the later Warner transfers go too far in the other direction.

Or it could be that maybe the 35mm sources project differently than the 70mm ones..who knows. The 35mm print is still the best I have ever seen and that was about 6-7 years ago from the Warner archive.

Guys, I have an extra Criterion CAV box if it helps. I'll need to just spot check it for any rot. The box is a bit beat up but everything else seems fine; I just got an extra copy in a lot once. It has color bars.