Name that fastener

Yep.....Rivnuts. You need a tool that works like a rivet gun to install them. If those are ok, and you don't have to remove them, use a little teflon tape on the screws when you put the rack back on. I did that on my 64 Belvedere wagon's roof rack screws, and it never leaked a drop.
Oddly enough this one never leaked even with a beat up dry rotted seal.

Of course, this is the desert where It rains a couple times a year lol

20210107_210542.jpg