In arcade auctions, I have been burned on hopes that things work. Best policy is pay for what you know works. If you see the cab up and running, pay(or bid in my case) for what it's worth. Do not pay "working" price for a PCB in a box (untested) or a cabinet that does not power on or at least assume it is non-working and pay for what a that it is worth "non-working" (cabs can be worth something for parts as a donor). I picked up a Naomi MvC2 cart in a lot of box random PCB's once, only to find out that the seller replaced the Naomi cart PCB with some horse racing game but left the cart housing from the MvC2.
Knowing that some folks on PCFX are wizards with repairs, factor the cost of getting it sent off to be fixed in your bid. Plus the CD-ROM unit is not some OMG R@RES item, there will be more come up...maybe one with the AC and tested.