What make? Ford, Chevy, GMC, Dodge, Plymouth, International, Studebaker, Hudson, and Willys all made pickups in '38. If it's Ford, try to find a pair of '39 truck hinges. They interchange with '38 and are a better design. They sometimes turn up on eBay.
The '39 truck hinges have a better attachment for the side panels so they don't rattle against the cowl.