Howdy and welcome to Airforums.com! This is where you can get answers to all your Airstream-related questions.
Hard to say what that trailer is worth, not knowing anything about it, really. Those long poles are the frame rails, and being steel, they rust pretty quickly. Can you post any photos of it, interior, exterior, wheels and so on? That might help.
Apparently there were not a lot of Airstream trailers manufactured in 1983, either due to weak demand because of world financial problems, or a change in ownership (I can't remember which). Neither fact should have any impact on the price, just that it makes it harder to find records of sales.
If you really want to give it a once over to find faults, go to
this page and you will see the second sticky thread is called Trailer Inspection Checklist. Download it, print it all out, and go over it in detail while at the trailer. You will soon get an idea of its condition.
ps: a dead furnace in a trailer almost 30 years old is not unusual. I bet you replaced your home furnace well before it was that old...