Hello gregsproat from Texas. Welcome to Air Forums. This is a very good website for you and your 63 Trade Wind. Hopefully someone will help you.
I have a 66 Trade Wind. The entry door lock was made by Bargman, mine is a model number L-100, which is a rotary door knob style lock. I rebuilt two of the Bargman L-100 locks to fit the unique Airstream "set back" of 3 1/2 inches. I do not know if your trailer has a cast aluminum door frame that is the reason for the odd ball set back dimension. Mine has a cast door frame.
I purchased a used Bargman L-100 on e-bay at an exorbitant price. These old locks are rare and thus spendy. But I needed the parts, and a Schlage $50 lock would not work due to the odd ball set back dimension.
I see there was one for sale on this website, but alas it has been sold. Here is the old link so you can learn a bit more about these old locks. Search the classifieds and you might find another one.
http://www.airstreamclassifieds.com/...with-two-keys/
And search the internet and see what you can find. Old Airstream door locks can be a problem. Just another challenge for the vintage trailer enthusiasts.
David