The Dodge WC-1 and the very similar WC-5 WC-12 WC-14 and WC-40, are 1/2 ton pickup trucks with slightly different engines and other small differences. All have a closed metal cab based on Dodge civilian trucks. All are part of the WC model series G-505, built by Dodge during 1941 or early 1942.
If you don't have the vehicle dataplate, to differentiate you must know the U.S. Government registration number (Army number on the hood) or the serial number which can be found stamped on the left front frame.
Data from SNL G-657 Dodge Master Parts List. *W-80766 was a single unit with no body. Other data on the Dodge G505 main page.
WC-1 Truck, 1/2 ton, 4x4 Dodge WC Closed Cab Pickup (G505). Hood number W-25979 confirms WC-1 (1941 contract).
Restored Dodge WC-14 on display at the Magic Valley Jeep Preservation Club Military Vehicle Show, Twin Falls, ID, 3 September 2007. Hood number W-0004035 is correct for a WC-14 (1941 contract). Door symbol and other markings are for the 9th Service Command, US Army. Photo courtesy John Eickhof, owner.