As soon as what appeared to be an unserialized firearm showed up the FFL had no choice but to contact the ATF immediately. Doing anything else could easily make him party to a crime, and certainly would put his license at risk. Remember, this isn't just something he does for fun. This is how he makes a living, how he provides for his family. The risk was losing his license, destroying his life and family, maybe even going to jail. All this over one lousy rifle for one "customer" who didn't even buy it from him. What kind of cost/benefit analysis are you doing that has you putting all this at risk?