In North America, prior to Greatest Hits, there were two versions of
GT1. They apparently differed mostly in Game Shark locations, but a few car names were different also.
http://www.geocities.com/gt2toxs/gt/diary/2003-12-27.html
http://www.geocities.com/gt2toxs/gt/diary/2003-12-29.html
http://www.geocities.com/gt2toxs/gt/diary/2004-02-01.html
I would assume visibly different versions of "Greatest Hits" would in fact contain identical software. Sony doesn't often seem to release an actual new "software version" gratuitously. (From which we can infer there was something they considered somewhat majorly wrong with very early versions of
GT1--but perhaps it was just the Japanese market names for some of the prize-cars).
I would assume that all
GT1 "Greatest Hits" disks would be "version 1.1". That is, I claim Sony is more likely to gratuitously change packaging (including disk printing) than gratuitously produce an actual new software version. But I could be wrong about that.
It's strange that in all the above pages I don't actually mention that the tiny "production run" numbers embossed on the hub allow you to distinguish different versions--identical numbers will be the same version, while different numbers might be the same version, or they might be different.
I listed some info at gtx...
http://www.granturismox.net/vb/showthread.php?t=6675