I believe MK1 in MKAK is 4.0 T-Unit (not regular 4.0). When you beat the game and it shows each character, the one you have used to beat the game will be in p2 pallete. This is fixed in 5.0 (T-Unit). There were few other things here and there, but someone also managed to enter in the audits menus of the games (i think it was for PC), but i lost the url (he made screenshots of UMK3 audits).
UMK3 is revision 1.2 for sure as Tim said (XBLA version is 1.1), and I have no idea what revision MK2 is, but its probably 3.1.