Hazards of testing battered keyboards?

I recently won a couple of the black Pro keyboards for a pittance on eBay. But (as previously ranted) the evil of UPS is always a dark cloud over the brightest auction find.

This is what the package looked like when it arrived.

The keyboards look fine. They were pretty satisfactorily bubble-wrapped and I can see no physical damage. But if they could have sustained mechanical or electronic/electrical damage that I can't see that is capable of zapping my computer in some way, they're not worth serious harm to a Power Mac G5 that I've struggled to keep in good working order for the past seven years—neither for purposes of keeping them as backup as intended, nor for purposes of claiming against UPS.

What do you think? What's the worst that could happen if I try to use a keyboard that's trashed somehow?

In case it matters, we're talking about this one—the M7803 model.

Thanks!!