Well, the interior skins of most 70's Airstream are a vinyl clad aluminum, not something you are going to find at your local hardware store. You're probably not going to find vinyl clad aluminum anywhere that matches yours unless you check out some of the RV salvage yards and get lucky.
You could find un-clad aluminum panels though at places like
Aircraft Spruce. Then apply a vinyl walcovering, paint, Zolatone of your choice.
Good luck with whatever you decide to do!
Shari