Sparky -
I may have misinterpreted the problem here, so please correct me if I have, but here goes...
It sounds like you're having a hard time seperating the concept of "ownership" from "possession". A person can be legally prohibited from possessing a firearm, yet still "own" it. That is, although they paid for it and have all property rights in the item, they are prohibited from physically possessing it.
An example...
A guy came to my office a few years ago after a major fight with his wife. When the cops came to investigate all the racket, he was arrested, and his wife filed for an order of protection (restraining order). Thus he could not possess a firearm. The cops took possession of his guns at the scene and, because of the order, refused to return them to him. The guns were still his, but he could not possess them and the cops couldn't give them to him. He found a buyer for the guns, all three of us went to the police station, he signed over all interest and title to the guns to me (an FFL) and the police released them to me. I then transfered the guns to the buyer. The buyer paid for the guns. The first guy owned and controled the guns (or value thereof) but he could not physically possess them. I guess the simplest example is when you give something to the valet parking guy or the coatcheck girl. You own the item, but they are holding it. They don't have title tothe item - you do. But in the case of a firearm, some people can just never retake possession - they still have title to the item though.
Sounds like you have a similar problem. You want to check with the person in possesion of the gun(s) and get something indicating who owns the items in question. If its the guy who claims to "own" it, you should be fine. Just make sure you get something from the "owner" directing the "possessor" to release the item to you.
...or did I totally miss the point of the question?