Handshake deals just don't make for good friends or business. As soon as money gets involved, either too much or too little, someone gets greedy or insecure. Then the fight begins. The three guys up stairs will become pretty testy if they are unable to make a go of the store. And the probability is they won't. I hope they make it but small gunshops are a dying breed. I am from Western PA myself. Look around at how many gunshops have come and gone in your own experience. Few have made it for a whole year - too much competition from internet, Cabela's etc. Protect yourself. In the end, having your own shingle and becoming known by being around that shop will be an asset for you. You can continue business after they are gone if that happens.