[superbirds]

That's a great idea for testing - Thanks Richard I've never used that technique. It should help for confirmation once I get things sealed up.
Not being much of a body man it's become pretty obvious I'm out of my wheel house on this one. I did look for any related posts on this site and didn't find anything related to the older classics. The good old internet and Google did provide something I should have known about but didn't. Automotive Seam Sealer - found this at Eastwood. Sounds promising - Eastwood Brush on Seam Sealer Quart. I also found some EternaBond DoubleStick from Amazon. Maybe a combination will work out.  We may also have an automotive paint supplier nearby that will have something.
I'm also going to remove the trim that holds the fiberglass front roof section to the front window upper sill. That one my be ever harder - I'm not sure how it's held on. Should be interesting. By the way saw pictures of your coach at Tom's - wow looks great !! Love the portable Starlink dish also. Too cool.