I have never seen the full four digit year, not the three digit month+year. I imagine the good idea fairy strikes the management now and then and they decide to change their headstamp for a bit, then i goes back to normal. Military issue 9mm you pull out of ammo cans today is stamped WCC, (NATO cross), and 10, 11, 12, etc. It comes in the same white foam holders that commercial ammo does, though the outer box is brown.