m1 bolt id

need info on a m1 bolt manf mar 44 till end of the war
D28287-19 SA A-5 with a diamond after the 5 this weapon redone at augusta arsonal
in 1953 what I don't understand is the diamond

thanks for your time

We think it signifies the new steel used from early 1943.

thanks for quick comeback all you guys are aces