I also have a couple 1440s.
I bought one new in the 90s for $4,000!
I bought one last year used for the original owner for $300.
The one I bought new is still very much usable and in good shape with 800 hours on it. The $300 one has numerous good features but the engine isn't running. I think that it will but my point is, even if the engine doesn't run, all the other excellent parts are more than worth the $300 I have in it and it will be good as a donor machine for my other one if needed.
As has been stated, once you sell it the machine is gone and soon the money will be too. Consider for a moment just how little $300 will buy these days. I'll keep them both of mine but at this time I don't need the $300...