What a great find very nice.
Ahhh those end caps, Argosy's have a predisposition to popping the paint off the steel, you are lucky only to the primer. A body shop recommended to clean mine up and use a rust stop treatment (pep boys has it) then using a roller use Rustoleum enamal tinted the same color. a quart will do both. When put on not to dry it actually smooths itself out like it was sprayed. Any water damage inside, don't use silcone to seal windows or beltline rail or rub rail unless you will never paint the sides ever.