Hi,
I don't think anything was killed by having one of the Kickstart roms backwards. It may short Address line A0 with A16 and *potentially* pull A18 high (all of which can halt bootup), but the symptom of this should be a red screen and not a black screen.
The fact that you received it with the rom backwards suggests the user trying to fix an existing (possibly non rom-related) fault
Edit: Have you tried booting with the ROMs removed?
