Some claimed that it is, but I never had it happen while playi g with a supergun. My only remaining cabinet's jamma connector is keyed and this isn't. So I can't tezt to see if it somehow behaves differently in a real setup, but what makes the most sebse is that it was just an additional (daughter?) board that was used for various consoles in arcade cabs.
This one is supposed to support 2 players, while that Western jamma adaptor does not.
I wanted to sell this as a lot with the unique Bonk 3 "HuCard" that it came with, but can't find it.