After Glock sent my 17 back with a new trigger bar of different design than the one it went in with, I was curious and checked the rest of my Glocks. What I found was, my 21C has a similarly contoured trigger bar (a sort of channel for the striker through the top of the trigger bar), and has 4256 stamped in that channel. AFAICT, 4256 is not the normal part number for a G21 trigger bar. In fact, I can't find reference to any Glock part #4256. I don't think I've ever seen another Glock trigger bar with a part number stamped into it. You can see pictures of the new trigger bar in my 17 next to a standard one near the end of this thread: http://glocktalk.com/showthread.php?s=&threadid=273966&perpage=25&pagenumber=2 What I'm wondering is, are the 17's new trigger bar and the 21's trigger bar new Glock part numbers? Are they new & improved stock parts, or are they problem solving parts only installed in Smyrna?