What are these fender gizmotrons called?

[BASE]

The bane of anyone who's ever removed the fenders from one of these old trucks. I just installed new ones from classic parts. In fact, once I saw the price on the front fastener kit they sell I decided it wasn't worth cleaning up any of the old hardware. My local Ace hardware sells the J-nuts as well if you are in a hurry. I was surprised to see they had the "body bolts" & weld nuts and few other fasteners I wouldn't have thought to look for there as well.