Welcome to the Air Forums! I hope you find it uiseful in your referb!
Airstream travel trailers from 1967
and newer had shcks that are mount horizontally. Meaning they are more parrallel to the ground than they are perpendicular. This was done to save on interior space. However it creates a valving problem internally in the shock. Therefore those shocks are only available through an Airstream dealer. Several dealers have websites so you can shop on line rather than driving to a store.
The brake linings are available at most trailer stores and are not Airstream specific.
Also look at your torsion axles. If your trailer has been sitting for 25 years you may have some issues with the flexing of the rubber inside the axles. Meaing there may not be any flexing.
Good luck and glad to have you aboard