Re: interchange to 1937 Pickup
Inner front fenders: 1937 1/2 ton only.
Front fenders: 1/2 ton only, 1936-37. (1935 fits except has hole for bumper iron, 1936-37 has slot. Steel fenders without bumper hole/slot are likely 1935-37 1-1/2 ton.)
Grille/hood/cowl top/cab front above windshield: 1937 only 1/2 ton and 1-1/2 ton the same.
Cowl vent/windshield: 1937-39 Pickup/Truck/Passenger the same, except minor details on windshield frame, regulator handle (1937 only) and regulator mechanism (1937-38)
Seat/seat platform: 1935-37 1/2 ton only, May be the same through 1941. (1-1/2 ton has fuel tank under seat).
Cab subframe/under seat pan: 1935-37 1/2 ton and 1-1/2 ton with some carryover at least into 1938. (Most or all 1939 used the 1940 sill design, I do not know exactly when the change happened. 1-1/2 ton do not use under seat pans)
Cab to frame blocks/mounting bolts: 1935-37 1/2 ton only.
Inside door and window handles: 1935-37 Pickup/Truck, 1933-34 Coupe/Sedan
Outside door handles: 1936 Deluxe Passenger
Doors: 1/2 ton and 1-1/2 ton the same. Some early 1935 had garnish moldings. Sometime in 1936 the window felt design changed to have felt all around the window opening, 1935 had bumpers at bottom of opening. All other door parts the same and any door will fit any cab (unless bent).
Year specific dash knob and instrument differences.
Most other cab panels the same 1935-37.
Bed front panel, stake pockets, rear crossmember, running boards, running board aprons the same 1935-37.
Bed sides, subframe, tailgate, and tailgate hinges 1937 only.
Rear fenders are 1937 only, there is a difference on the inside front (that cannot be seen from the truck exterior) having to deal with different clearance for the cable brakes. Otherwise 1935-36 will fit.