Welcome to the board.
I doubt the PO broke it, it looks like it was worn through from the tab on the striker spring guide.
Sometimes they can chip, but this one looks just worn.
It can be fixed, either by welding and re-milling or other means- though I don't know anyone who undertakes this repair as a vocation.
I recently repaired a similarly worn breech block of mine by inserting a pin from side to side and re-shaping it a little.
I've been meaning to post the process, just have not gotten around to it. I'll move it up on the "to do" list.
http://forum.lugerforum.com/showthread.php?t=35951
Done!