I'm in the middle of a complete house remodel that's going to get me my game room, so I can't get to my Playstation at the moment to confirm it, but...
I don't think the Guncons work for the Area 51, Maximum Force, Lethal Enforcers, and the like.
Those work with the Konami Justifier type controller, which the Guncons don't emulate.
I picked up a couple switchable guns that will work for those, but they are not as good as the Guncons.
The Guncons are much more responsive, which is most noticeable on the "shoot the train" stages on Point Blank.
When you have to get off alot of shots quickly, the Guncons pick up every shot, whereas the others that I have will miss shots.