A good one to try is NBA Jam or NBA Hangtime. NBA Jam will ask for initials for record keeping. I think you can just play a single quarter and it will keep your initials. Then quit MAME and start it again and see if your record exists when you enter your initials again. Same thing with Hangtime though you can very quickly create your own player and then quit and see if you can get him to come back up again.
Actually, both of those games report CMOS errors on initial startup if nvram cannot be found, so that should even be enough. Start the game, play for a minute or two, quit, start back up and see if you see that CMOS error on boot again (it’ll be in RED TEXT).
And the input remapping functionality is GREAT news.