I am working with a gentlemen who wants to buy a shotgun I have for sale. I know I need to send it to an FFL, however what information will I need from the FFL. I am assuming I will need his FFL number, which I am assuming I could jsut call and get over the phone. Obviously, I will need his address but how can I be assured that the address I am given is actually an FFL? Any information would be appreciated.