Just looking at some of my stuff I noticed a Z marked on the trigger guard of my 54 CZ52, what does this signify? the gun looks unissued, aside from the 50 rds I pu through it. It has a refurb date of 96 0n the other side, none of the usual peened "accuracy dots" on the slide. Also just out of curiosity I have 2 CZ52's, both had the pin walk out of the slide stop the first time I fired them, easy fix (staked the pin) but why would they rearsenal a pistol with a pin that would walk. Seems to me it would not be an ideal situation to have your pistol freeze up after one mag in a heated moment. Any one else have this happen. Both pistols shot bad groups initially but tightened up considerably after I staked the pins, as the pin has no effect on the barrel it has me stumped. Just wondering if any body else had the same issues. I've never seen a post about the pins despite the number of these pistols sold, I ordered mine a few years apart so I know it is not a "batch" problem.