If there are no hidden problems, that could be a nice deal. Of course, it's always better if you can get it for less, but if the floor is solid and all systems are working, with new awning fabric that price is in range.
As has been said above, make sure you have good enough tires for the 200 mile tow home. Having a tire disintegrate and beat up the skin and the wheel well gets expensive in a hurry.
Typical for Airstreams and Argosies of this vintage, it probably needs new axles. This isn't actually a big deal, and you can order new axles complete with new drums and brakes, already assembled that are a bolt-on (or near-bolt-on) upgrade. (see many axle-replacement threads, including mine.
The very-original interior looks pretty nice. I have the original cushions on the dinette, but the previous owner redid both of the mattresses (mine's a twin-bed plan) so I don't have nearly as much retro textiles as this '72 includes.
Good luck! I hope it turns out to be a good deal for you. Inspect, inspect, inspect... it's OK to buy something that needs work as long as you have an idea what you're getting into.