My DC offers me an Arcade mode when I play this, so I'm assuming that this was released as an arcade machine, at least in Japan. I'm also remembering that when you stepped up to HOTD in the arcade, you unholstered your piece, labelled "The Gun of Justice". (Unfortunately, with the Cleveland arcade scene being in the toilet, I've not seen a HOTD2 in the wild.)
So the question that haunts me is this: In the arcade, did they go all the way? Was there a label saying that you were using "The Keyboard of Justice"?