Kemps,

3800 series = 1 ton, wheel base of 137 inches

38xx : xx=04 for pickup; xx=05 for Panel

3802 = chassis and cowl and flat-faced cowl (no cab, bed, or rear fenders)
3803 = chassis and cab (no bed or rear fenders)
3804 = Pick-up (bed and rear fenders)
3805 = Panel Truck
3807 = Canopy Express
3808 = Platform (stake pocket rear - no rear fenders)
3809 = Stake (3808 with factory stake bed/sides)
3812 = chassis and cowl and windshield cowl (no cab, bed, or rear fenders)

3804: GVW = 7,000; 5.14:1 rear
3805: GVW = 7,000; 5.14:1 rear

Tim