I had a '76 Overlander that had missing rivets behind the beltline & rubrail stripes. It took me forever to find those (sealed all windows, vents, etc first). I had a wet floor after rain, but nothing coming from above it. After I discovered the missing rivets & repaired those, I went all the way around & sealed every rivet under both the beltline & rubrail stripes. No more leaks after that. Good luck!
1964 Bambi II
1988 Avion 32S