what if the box is sealed but the s/n is differnt

I go camping in PA forests. Is it legal to fire a shot gun for target practice in a PA state forest?

Are the 25 digit codes activated at the register or in some other fashion at the store?

Or would it be better to go to Sears or maybe Best Buy?

If theres any specialist out there that could tell me what it’s like I would appreciate it.

My friend just got his second interview done and is really close to getting the job but the thing is he is also about to land a job that will give him around $11-13…so how much do they get paid? (btw he lives in FL, just incase location matters)