To All Interested:
I took our coach in to the Dealer where we purchased it for various maintenance issues and to asses the problem with the roof separation. The tech that was accomplishing the work looked at the problem and proceeded to fix the fault. I had described to him that I had discovered the rivets had rusted, Well to be honest, they were not rivets, but Very Rusted screws. The tech pulled the protruding part of the screw out and re-drilled the existing hole. I believe he was having some difficulty drilling a steel screw out and ended up using a punch to hammer the rest of what remained of the screw through. In my opinion I would have just drilled an adjacent hole. The type of fastening device used was an aluminum 1/4 inch rivet 1 1/8 to 1 1/4 inches long. Wish he had siliconed the hole before inserting the rivet, but he at least siliconed over the head after setting the rivet. This has taken care of the issue for now.
So, I have concluded, that Beaver used steel screws for securing the fiberglass roof into an aluminum frame, thus setting up a situation of the screws corroding due to contact with a dissimilar metal (learned that in the Air Force). Aluminum can corrode as well, but the steel goes first, so I hope the aluminum where the screws were have not corroded too much. This is why, I believe drilling a fresh hole adjacent to the old screw hole would be better, as Ed had stated was the procedure he used. Just a bit of caution to anyone with a Beaver of our vintage, check your fasteners under the rubber boot along the side of the gutter. I plan on redoing both sides of the roof line once I get the parts. Ed had used an aluminum screw and if I can find this type, thats what I will go with and if not, an aluminum rivet will work as well, I hope.
Ed, Thanks again for your help and pictures.
Adam, I have taken some pictures and will post them, with some help from my wife.