Zakk,
yes an official Sega CP will fit perfectly, I breifly owned a Naomi clone last year, firrst job was fit a new CP .
NO its not wired to JVS - if it was wired to JVS, it would cost a fortune, JVS or "JAMMA2" as it is known to some, uses some fairly expensive I/O boards, stereo amps and PSU's - at best the cabinet will be wired to JAMMA with a cheap generic china brand PSU.
to be honest, when I got mine, I had to more or less rebuild half of it anyways to sort out some earthing issues, monitor discolouration, new CP, extra wiring harness and generally making sure the cabinet all sat flush, originally it looked like it had been thrown together and nothing sat right (CP surround for example was not flush with the monitor plastic surround)
IMVHO - pop a tri res 29" monitor in, use a decent PSU and a new CP instead of the china brand knock off buttons/sticks and they make a good cabinet, not a patch on the real Sega cabs tho but they do do a decent enough job structurely.
slight note, the Naomi clones weigh approx half as much as the real deal