I also have this knife, which I got from an Amoskeag auction in January 2014. It is also in the Stidham/Crider catalog; #P-257 on page 36. Rhett called it a "Special Model 24 Guardian". It was authenticated by Perry Miller in March 2014 and Perry called it a "very unique boot knife" resembling a Gambler.
It bears a passing resemblance to Eric's "humpback" knife.
- Buckspen