Airstream 250 manual and background
I stumbled across this old post and can help clarify the issue. Airstream didn't produce a manual for the Airstream 250 Motorhome because it was produced in such small numbers (general concensus is fewer than 50). My 250 came with a manual for the models in the same series (290/325/350), but i had Airstream 250 written on the spine and the stock number. However, it also had a 10 pages of specific diagrams (electrics/plumbing etc) tucked into the manual cover which relate specifically to the 250. I'm happy to share these with you or any other 250 owners, just PM me with your email address and I'll pdf them across to you. I've spoken with Airstream about the manual issue and like you they hold no documentation other than the old price list with options which is on this site. The manaul and inserts cover pretty much everything Airstream had to offer on the 250. I also have the Chevrolet Motorhome chassis manual from 1991 which has almost everything on required chassis maintenance. There is a more detaled chassis manual (which was made for Chevvy garages) which has yet more info.
It's difficult to assess exact numbers which were produced, but I would estimate there are still about twenty kicking about which I have seen photos of. There were different configs for the 250 with twin settees, dinette or cocktail chairs. Some think they were made by the Commercial Division, but I don't believe this to be correct. There are some which were Ambulances which may not have come out of the standard factory set-up. I think the 250 was probably special order. I've heard people say that they were all LE models and the standard 250 issue did include LE Graphics, but I think the defining factor on whether a 250 is an LE model is whether they have most of the LE options i.e. Corian counter tops, leather package on seats and settee, lambriquin close outs, and ozite ceiling (which is the fabric walls and ceiling). These are shown as the LE package on the 350 options list. Hope this helps. Let me know if you need any more info. Nick