Hi Steve,
I would also suggest pursuing Paul Varga first.
Another fellow and I restored a 250 to manual operating condition (didn't want the kiddies getting fingers caught in any moving parts running it electrically) for the CAF-Wisconsin Wing. This was a good 10+ years ago, but I do recall working with a complete photocopy of the parts manual. Perhaps they or even headquarters could point you in the right direction for getting a copy of your own.
As was also mentioned, I'm guessing there is no one parts manual that covers all the mods; so if you're planning a restoration be prepared to make some educated guesses!
Happy hunting!
