Rick - According to research through several Chevrolet Master Parts Books, the 1941-46 trucks used the same bumpers for both front and rear, with the exception of Suburbans, Panels, COE's and Utility trucks equipped with the channel type front bumper. The passenger car bumpers were different part numbers for front and back, as well as different from the truck bumper part numbers.
No idea what the difference between passenger car and trucks are, but perhaps that info is out there on the web somewhere? I may do some snooping to see if I can find anything relevant.
