Greetings from Colorado: Welcome to these Air Forums Connollydvm. There are folks here who can give you some unofficial "appraisals" with additional information. Actually lots of additional information is needed.
The first thing to do is start your own thread in the Dollars and Cents, then "Trailer Values" subcategory. Your 1949 Airstream might look kinda like a "Liner" with that unique front window. I think Forum participants would enjoy offering their opinion on the value of this antique Airstream.
Post several good pictures of the trailer in your thread so folks can see all of the body, and some interior shots as well.
Then describe the trailer the best you can. Your assessment of the axle, bearings, brakes, frame, subfloor, body, windows, door, and other systems help determine the value. I think this year had that "pipe" and ladder frame.
There are folks on these Forums that thoroughly enjoy restoring these old Airstreams and showing them at rallys. Your old trailer has value of course unless a tree happened to have fallen on it and crushed it. Buyers need to determine how many dollars it will take to restore this trailer to "as new" condition. It will be a lot of dollars for sure.
Hope this helps....