The volume of pre-torsion spring Airstream trailers (Circa 1961) that are left are few. There wasn't many build to start with. The manufacture for those springs may not be in business either.
The good news is nearly any spring shop can handle the job. However living at the North Pole may be problematic as the number of spring shops there many be non-existant.
Not a problem, you can buy these bushings online by size. Just like a bolt. There are several dozen choices on line. I have purchased truck springs on line with very good results.
You would need to know the width of the spring which will be the length of the bushing. The size of the eye of the spring. And the bolt hole. Replace all hardware that is removed in the process, including spring to axle mounting bolts if the spring is being removed from the vehicle. 60+ year old hardware is not good to reuse.
1966 Mercury Park Lane 4 DR Breezeway 410 4V, C-6, 2.80 - Streamless.
1966 Lincoln 4 door Convertible 462 4V 1971 Ford LTD Convertible 429 4V Phoenix ~ Yeah it's hot however it's a dry heat!