Hi I recently bought a my first gun... a Glock 20SF. I bought it at a gun show so the gun was out on top of a Glock box. All the guns were displayed like this. The dealer told me that it was brand new. My question is in the Glock case there is a little manilla envelope with the Glock address on it, inside the envelope is two empty shell casings. (1).Why are these two casings in the case. (2)Do all Glocks/Guns come like this (with shell casings) as far as I can tell the envelope is from Glock.