Recently picked up a M4 Bayonet and it had a series of numbers on the back are these identification numbers? There are four numbers on the back similar to the "Last four" the mil uses today. could these numbers help identify the original owner of the knife?

Those would be the manufacturer's production number/part number .

Bayonets are not issued to a individual, they are just "signed for " at the QM stores. Not traceable to an individual soldier, I'm afraid.

Jim B. Toronto.