If it is dated the markings would be on one of the flats of the hex head...
Did you find it's sheath?, they were dated on back.
I found the sheath, it appears to be old enough to be original, but no dates
From the info above it seems it would be made between '57-'61.
I went back to my grandpas garage where I found the knife and I also found a list of his gun serial numbers. I own all but 1 so it sparked some curiosity.
It read : 45 model of 1911 US army #258591
That was enough for me to ask my mom about, the story is that my grandpa's brother brought it home from WWII and my cousin has it now. I'm gonna have to check it out next time I go down to Mississippi.