1995 F-150 Wheel Hub Nuts

Some of the hub retainer screws have broken off and I need to replace them. The Ford dealer had no idea how to get replacement nuts. Does anyone know what company supplied the chrome steel OEM wheels to Ford for the 4x4? The nuts are 1/2" OD and pressed in. They accept 1/4-20 special chrome screws which the dealer was able to provide. Thanks for any help you can give me and please don't suggest an easy-out as the threads were very corroded and the heads broke off while trying to remove them to change tires!