Most of the main points were brought up. That cabinet was originally a dedicated 4 slot neo-geo, which would mean it was originally wired MVS and not JAMMA. If it has a single slot MVS board in it now, they either have an MVS->JAMMA adapter, or someone has rewired it for JAMMA instead of MVS (MVS has stereo sound).
The marquee to get back to the four mini marquees probably won't be too bad. As far as the lighting behind it, someone is working on an LED solution that will be much cheaper than the original EL panels (Which I wouldn't recommend to go to for cost reasons). Everything else on there looks to be good shape. Monitor seems to need a recap, but that is reasonable. You will need to open it up (the control panel will unlatch and swing open) and check if it has a 4 slot board or a 1 slot board inside. If it is the 4 slot, it is still wired MVS, so only change out the button colors, recap the monitor, and replace the marquee holder and you are good. If it has a 1 slot with no MVS->JAMMA adapter, then it has been wired for JAMMA (you could easily get a JAMMA->MVS adapter rather than rewire it, and it will then take a 4 slot without issue.
There were several dedicated NeoGeo machines... although most were just the generic neogeo, but as mentioned there were dedicated Samurai Shodown machines with different artwork. Pretty rare though (whitish cabinet).