It clearly has pins for buttons 4, 5, and 6 for both players one and two on the weird "Paradise Elf Adaptor", whatever the f*ck that is.
I'm really interested to know WTF this board is. I mean, the Neo and CPS are really similar systems, but I've never seen a system that will run both. I have seen PCBs that were basically a PC running a shitload of games under (questionable) emulation. That's probably what this is, but it sure doesn't look like it.