Ok, time for a sanity check. The 7750 was used in Allante from '87 to '89. The 4.1 calibrations look consistent enough to work on disassembling but the 4.5 looks wrong. It may be completely unique but I really have to wonder because GM loved to re-use code. You can find the same code snippets in vehicles from the first CCC cars all the way to the ZR1. Even GM built race / custom vehicles from that period used stock code with trouble codes and emissions functions shut off. They may have created something unique for a one year only configuration vehicle but it seems strange when they already had working code for that ecm and vehicle.

Unfortunately it looks like there were only two calibrations for the 7750 / LQ6.
ANSU7126 and ANZR9603. If we had ANZR we could at least look for similar bytes in the preamble.

Out of curiousity, have you tried burning ANSU back into a chip to see if the ECM accepts it?