I'm puzzled by the track numbers. On other sets, it seems that the first digit represents the act -- track M21 is the first cue in act 2, M22 is the second, and so on, with the teaser and act 1 going together. But here we've got first digits going up to 8 for "The Cage" and 6 for "Where No Man," even though they had 4-act structures back then.
I believe those numbers are similar to the numbers featured in the film soundtrack liner notes; corresponding to film reels(?), not to "acts" or anything like that.
EDIT: Oh, okay, slate numbers. I was close!