Here's a couple of pictures of an interior removed front and center on a 1963
22" Silver Streak. Some differences that I notice from Airstream construction are: Plywood surround for electrical outlet, the insulation was held in place with a tape that overlapped at each side of the rib, ribs interiors have some type of rubberized substance insulating them from the interior skin, the c-channel at the floor is aluminum. Nice place for a leak! Right where all the electrical connections are made! I think the source of the leak is at the unsealed access cover on the exterior.