Hello from Colorado and welcome to the vintage Airstream hobby. The
Caravel is a very popular vintage Airstream, congratulations on finding one. They are rather hard to come by. Yours looks to be in good condition.
The trim you show in the photos of your new trailer is not likely factory installed. Here are some pictures of
1965 Caravels and none of them have the trim like yours does.
http://vintageairstream.com/photo-ar...-caravel-17-3/
Having this trim added, and having a non stock rear bumper does not necessarily indicate a body off restoration. The seller should have had some information on the history of the trailer. People take the bodies off their Airstream usually for a total subfloor replacement and/or major frame repairs. Look for evidence buy studying the subfloor, front body mounting plate, and belly pan. You might see newer rivets, newer wood, or newer aluminum. You also would expect new plumbing and newer electrical components. That evidence might indicate a body off restoration seems to me.
I might add that the trailer ride height is indicative of worn out axle rubber. It looks like it sets pretty low. A normal guy wouldn't likely go through the effort of a body off restoration and leave an old axle under the trailer. So that is another clue you could check out.
I had a 66 Trade Wind 24' for a number of years. I did extensive renovation to the trailer, but not a body off frame. It did not, or does not have the body trim molding along either side of the trailer. It does have the molding along the front and rear end caps. The trim above the wheel wells is a "tire curtain support". It was an option where you could install sun blocks for your tires. Here is a photo of the old 66 Trade Wind showing no side moldings.
I gave thought to adding the molding along the sides of this trailer just to break up the "slab sided" look. The new body style came out in 1969 and most of those trailers have a lower molding in the area where yours is showing. I now have a 75 Overlander 27' and you can see the lower moldings go all around the trailer.
I might add that Airstream built the mid sixties trailers with the exterior skins on the sides of the trailers wrapping around all the way to the belly pan aluminum. They changed this technique sometime in the early seventies.
David