The reciever of stolen property was the gun dealer. I suspect this dealer is attempting to launder stolen guns. I suspect that was completely negligent, or was willingly a partner in a lucrative fence op.
Since the dealer is engaged in commerce and advertises that he is legit he should verify the stock he puchases is legit. He has a lawful duty to reasonably do that in business law, if not by statute. The duty in this case is the one engaged in operating the business, not the customer. This isn't a case of private sales, where the seller presents no advertising of legitimacy to the general consuming public. The database does exist and I suspect at this point the local PD had the info that the gun was stolen and the gun dealer was at least negligent and likely a willing fence.
The dealer ain't the guy who showed up at the Canadian border with a stolen gun.