Glock 20SF

Question
Hi I recently bought a my first gun a Glock 20SF. It was 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. I got it for a good price. 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 come like this (with shell casings) as far as I can tell the envelope is from Glock.

Answer
Depending on where you live, I have heard that this was a new program or law that allows you to match your gun to the shells that have been shot from your gun.  I have never seen this done, but I would call glock and ask them, if it came from factory they would know.