I think it was Jim Carter that told me that they are very rare, dealer installed option. Not sure what that means. I have a second set for my next project. I don't see them very often for sale. Kind of like the underbed spare tire carrier lock and a few other things that don't come up for sale very often. They are designed specifically for this vintage chevy or gmc truck since they fit the spring perches exactly right. Not for certain on anything. I wasn't there like you. LOL! Chevs of the 40's sells the new rubber bumpers for them.
