I saw a table at the Rochester NY gunshow selling "G.I." 7rnd. mags still in brown paper pouches for $8.00 ea. The claim was that they're made by a gov't. contractor to mil. spec. I was wondering what to look for physically on the mag to support this claim. I did handle a few and they seem well made, the next time they're in town I wanted to stock up- Thanks for any help.