Robeson Cutlery was one of the contractors who made the Mk 2 for the Navy during WWII. If it is marked Robeson Shuredge on the blade, it was made in 1943. If it is marked such on the guard, it was made later. That's about all I know about them. I don't really know what they're worth as I've seen prices range all over the place. I suppose it depends on the exact condition, sheath, all that kind of stuff.