If you are talking about the civil version of the WW2 3/4 ton truck built from 1946-68, then no, but there are some nice ones in diecast you can start with. Ertl and Matchbox both did a nice diecast 1/25 Powerwagon. There is also a resin kit if you hate working with diecast.
If you don't mind a smaller scale, the WW2 3/4 ton has been done in 1/35. There isn't really a lot of difference between the military and civilian versions that would be noticable in 1/35 scale.
The has been no kit of the Korean era M37 that I know of, but there is a 1/25 resin kit of the late 1950s Dodge pickup that also carried the name Powerwagon.