To clarify the revisions:

The arcade game has three total versions: v1.7, v2.3(W) and v2.3(J).

1.7 and 2.3(W) are quite different in gameplay. Some specials behave very differently, and AI patterns were altered to a great degree. The limit on combos increased from 14 to 20, with most requiring jump cancels in the corner to get above 9 or 10. Lots of balance adjustments as well. Damage, while still high, scales more aggressively.

If you were to try out primrage.zip in MAME today, it's going to be 2.3J, with primrageo.zip representing 2.3W. Despite only the region change in its designation, 2.3(J) is a whole other thing. Two of the AIs have changed (Sauron and Chaos), there are also some very minor balance changes, but the biggest changes go to the inputs.

Start is separated from the other four buttons, and most specials can be performed on positive edge more easily. Namely, three button specials now require just one; any special or finishing move input requiring the Up direction has been changed, and the Eat a Human input is now universal instead of unique.

If you have a genuine PCB, the program and MO roms can be flashed to 2.3J if you like, but I suggest getting a spare set of chips rather than flashing your originals.