Also looking forward to seeing pictures. Is there only indications of one set of numbers on the skin?
Keep in mind the WBCCI numbers don't follow the trailer, they follow the owner as long as the owner remains a member. Once membership ends, the number can be assigned to a new member. PM 66Overlander, the club historian, and he can research the number for you.
When he did my research he found different members in states based on the yearly directories for WBCCI. In cleaning out the trailer to prep for teardown I found materials from the 3rd owner (WA) only. However, the WBCCI Caravans decals/medallions align with the 2nd owner (AZ).
Attached a copy of my correspondence with Joe to give you an example of what can be surmised with your trailer/WBCCI number, but not necessarily documented.
History of #1996 and the WBCCI.pdf
Renovating a vintage airstream can be a long haul, but entirely worth the sense of accomplishment to see it go on for another 60+ years.
The members of Airforums will be here to help you in any way we can if you decide to go down the path.