Does that cabinet also have a network connection on it?
I'm not 100% sure but that looks awfuly like a Intercard system, where you would by credits at the entrance to the arcade, and then they give you a swipe card. the reader/display communicate with the arcades credit system over the network, the card just has an identification number, the computer in the back takes care of all the rest.
Getting it going with mame wouldn't be the hard part, as most these systems simply use a relay closure to simulate a coin drop to the game, but getting it operational without the credit systems computer would be a challenge.
SD