If it is camp ready and needs nothing that it an ok price. Rarely is a trailer of that age in perfect shape. Most have rear end water leak problems and some floor and frame rot. I believe the floors of that era are OSB which tends to fall apart like soggy card board.
Look under the beds in the back and pull up the floor covering till you can see the OSB subfloor. If you can stick your finger through it, then you have a problem. If it spent its life in NM then it might be a dry trailer. Anything that spent a significant portion of its life on the east coast is suspect.
It would have to be immaculate for me to pay that price. AC units are usually dead by then. Furnaces are near end of life. Fridge may or may not be in bad shape. The water heater is probably about done. Does it have new tires on it? This means less than 5 yrs old. Tread don't matter. Age is important. Does it have any damage to the skin? Is the clearcoat intact? Do the water and propane systems work? Are the sewer valves leaking? Are the bottom skins corroded and coming loose. Are the exposed parts of the frame rusted, especially in the back and front? The trailers with the horizontal propane tanks in the front have some front end separation issues. All Airstreams have potential rear end separation issues caused by corrosion and water intrusion.