Between the Roofrail weatherstrip retainer & body

[Dusk Blue Z]

The dust that was left when I took my car apart looked like open cell foam with an adhesive backing, just like the home window weather strip sold at the Loews and HD. The sticky side was on the moldings so it was easy to clean off the residue. I can look to see if I still have the package that would give the width and thickness of what I used. When installed it should be just about completely collapsed by the screws. I think it might be used to stop wind noise as much as keep water out.
Mike