There was alot of civilian knives that were procured durring the war and issued to the troops with little or no change to them. My Uncle Mikes stockman was a standard knife exept that an etch was put on the main blade "U.S. Government". I think at the start they were using anything they got, then later as things geared up they had definate U.S. issue knives like the all steel MLK issue knife.
I know in my own time in the service, GI's showed up with whatever was sold at the PX. Even though our supply had the all steel scout knives, the Buck's were sold at the PX so you saw a heck of alot of them in the field.
Camillus, Imperial, PAL, Robeson, Utica, all had their knives bought by the armed services at one time or another. It wouldn't surprise me if that Hammer Brand got snatched up at some time for a ships supply or something. I had a buddy that was in the Navy back in the early 60's, and his ship had boxes of those Kamp Kings that some procurment officer had picked up. Handed them out like candy canes at Christmas, so everybody on the tin can had one.