In the 1955 Dodge truck parts list, it shows only the C-3 PW 1 ton power wagons. The start of the new W500 series 1-1/2 to 2 ton 4 wheel drive trucks came in 1957. Those don't use the 10 lug wheels as your truck shows. They use 5 or 6 lug wheels.
Your truck looks to be a 3 tonner with a military type front axle and the factory Timkin/Rockwell rear axle. The data plate on the firewall or drivers door pillar will tell all.
Shown is a 1955 DT 3 tonner data plate I parted out a few years back. Had a 331 hemi with air brakes and the same rear axle as yours.