Perhaps a recurrent question, with no recurrent answer. Airstream might not even know.
Vehicles in the olden days...
“Dry weight” was as it rolled off the factory floor before adding battery, gasoline, antifreeze, oil, and maybe some other consumable stuff.
“Curb weight” was ready to go with gas, oil, battery, but no passengers, no cargo or roofracks, hitches, curb feelers, fender skirts...
I recall reading that airstream weights were “Dry” meaning no propane in tanks, no air conditioner, no water, no batteries... There's a list somewhere indicating the all added weights of each of the options.
I’d say that for any same-length airstream, older is lighter. You can make a seventies trailer work. A new twenty-footer weighs more than a thousand pounds more than my 1968
Maybe a 1970 tradewind, still had real wood interior, no tambour doors, single-pane windows, shortest tandem axle less likely to have bent frame… Nice, fairly light core to rebuild.