it's a direct port of the arcade version... and this version of MK was never released on the SNES... it was only ever released onthe Saturn outside of the arcade because Sega bought exclusivity.
You're probably confusing it with Trilogy which was a different game altogether...
Trilogy was a console only game that was basically just the first 3 MK games all rolled into one with a few extra features. IMO it wasn't that great of a game because it was horribly unbalanced and very buggy.
UMK3 was an upgraded version of the arcade game. when MK3 first came out Midway boasted that they'd do updates with new content in the arcades every few months.... they only ended up doing one update and that ented up being Ultimate MortalKombat 3. It had a few extra characters, a couple extra levels and a whole lot more VS screen codes.
Trilogy used MK1, MK2 and the base version MK3, they added brutalities in addition to a few new characters... again only ever appeared on the console and was done as a last hurrah before jumping to 3D.