2 things to consider:
#1 it's not a dedicated Neo Geo, rather a Dynamo cab.
#2 it is a 1 slot board.
I would say with 99% certainty, that this is a jamma harness in there, and that if the cab has stereo sound, it is not wired through the jamma harness. If it does have stereo sound (the MV-1 boards had the option for stereo) it is done through a "kick" type harness, not through the Jamma harness.
The only reason I won't say 100% on this is it is remotely possible that this cab originally had a 2,4, or 6 slot board in it, and was originally wired for that, and someone yanked that board and threw in a 1 slot. I strongly doubt that this is the case (since if it was, the 1 slot board would potentially be damaged as well), but you never know.
One more thing, if you want to rest a bit easier, the NeoGeo Pinout doesn't use a -5v, so check your harness (like the one pictured below) and see if there is a wire going to the -5v pin.(and make sure the wire is hooked up to something) if it is, chances are much better that it is using a jamma pinout and not a neo-geo pinout...
Disclaimer: Your mileage may vary, don't try this at home, the opinions reflected here are mine and may or may not apply to your situation, following this advice may cause discomfort or redness, if you experience severe swelling, discontinue use and see a doctor at once.
In other words, We are not liable for any damage to you or your stuff
