I'm not sure how I feel about this whole situation. It kind of screams "stolen merchandise" to me, but you'd be surprised the kind of offers pet store workers get for trading or buying animals or equipment. I've had a few people ask me to build them a rack like the one I made for myself, and I've had one offer to buy the one I already made, and people are always asking if I want their snake/rat/cat when I express a common interest. Not impossible, just improbable for that price I think.

The challenge in this situation I think is that even if they're stolen, in the state that OP and I live, balls are permit-only snakes. DoA here makes it near impossible to get one of the permits, so if they were stolen the rightful owner couldn't go to the police without admitting to a crime.