[DSPTurtle]

Yes, this particular picture is of a head that was R&R'd for a 930.
But might question is more generic. And it has more to do with the bottom row of markings... What does each marking mean?
I assume one of them is a quality control inspector stamp, maybe?
Also, where the second picture posted above has a 4, my original picture has a 2... I have seen these numbers mixed on running engines that we have torn down after being in service for a long time.
I guess I was hoping one of the machining masters would share this little tidbit, but maybe it's some secret code! Haha.
Thanks in advance