There are actually tell-tale markings which would give you a better idea...I'll bet that is what they are going to look at when you take them in.They may be all factory rounds but there is no way to tell.
If you're lucky, they'll turn out to be a bunch of loose shells that were just put into a handy box for sale.
I would personally not shoot reloads that came from an unknown source...time impart some wisdom on your son about the meaning of "as-is"