Take a gamble. If the guy wants to see or shoot the gun later, then explain to him later why you exchanged it. Not sure about the F.I.L., but I personally am one of those guys where I would much rather someone be happy with what they receive then not like it. If that means exchanging a gift for something better, then go for it. I guess you could just consider me an ungreatful SOB, but I am willing to bet there are more like me out there.