Sure...but explain why he had someone else's gun. What was he doing with a surveillance system? Except for the pot bust, the cops basically have him on thought crimes. Granted, no crime here if he has the paperwork and bought the guns legally. That is the question. I don't know what the legal age for gun ownership is in that state either. Let's just say the incident is highly suspicious.
Interestingly, there's no Pennsylvania registration of firearms, including handguns, now...so it's not clear about the .357.
The legal age of possession of a handgun is 18. A license is required for handgun carry (with some exceptions).