Seam sealer between fender/body?

cawley said
You can buy a thin foam strip from classic ind. When I took my 69 cuda & 74 challenger apart there was something like it.

Those who put camper tops on truck beds call it cap tape. It's nothing more than a 1/8 thick 1 inch wide foam like adhesive backed weather strip. I know that is all the factory used there from 67 up . I don't know about the earlier.