Does your knife have a 4" or a 5" blade?
If it is a 4" blade then it would be a 598? knife. Meaning it "MAY" be a WW2 era 598 variant. Per Gunsil, the bestest Kabar guru around, it is similar to a 598, but it never shows up in any literature or documentation that he has (and he has more than anybody, including Kabar). Were it a "real" 598 with a 4" blade, the designation would have been 598-4. But since no 4" 598 documentation has ever been discovered, it gets a "?" insinuating "maybe it's a 598".
If it is a 5" blade, it would be a 598-5 variant, most likely made in 1945 using left over MK1 pommels.
The 598 was a 1930s - 1940s knife with an aluminum pommel and the 5 (at least) had finger grooves. During the WW2 years, the pommel was wood or wood with a thin steel "overcap". The 598 was made with 5", 6", 7", 8" & an advertised but never seen in the wild 12" blade. The Boy Scout blade etched version was made from 1937 to 1948, BSA model 1553.
Kabar made a version like yours (flat steel pommel) w/ a 5" blade for the Boy Scouts that has etching on the blade, also designated as BSA model 1553 in 1945. The scout knife info comes from the book "Official Scout Blades" by Ed Holbrook.
I have several of the 4" and 5" flat steel pommel knives, but only 1 of the 5" blades having enough of the etching remaining to positively ID it as one of the BSA 1553s. None of my 4" blades have any BSA etching visible, but they are also have significant "well grayed" patinas. Etching may or may not be present on them.
