I have a 1941 pickup made in Oct. 1940 in Janesville. It has slotted interior screws. Only 7 or so clutch head screws in the entire truck. I needed some replacement slotted interior screws for it so I took them out of a 1940 pickup. It has philips screws holding on the door hinges
I have a 1941 parts truck made in Dec. 1940 in Janesville. It has clutch head interior screws. The door hinges are also held on with philips screws. Later trucks have clutch head screws holding on the door hinges.