The hollow "T" marking underneath your rifle's barrel appeared on virtually all CMPicon Greek rifles. The origin and meaning of the marking is unknown. Presumably, the marking originated with the Greeks, but that has not been confirmed. The "K" in your stock's cutoff recess is a common Springfield Armory subinspection mark and should not be confused with a similary "K" stamped in the cutoff recess of stocks made by Keystone during WWII.

Stay safe!

J.B.