What I would do in that situation is try for a good price on both guns like 110 the strip the rusty one and soak all the parts in Evapo-Rust and clean them up then polish the mating surfaces and order a new barrel for it with a bit of polishing it should be usable or saleable.
I would not try to force the action to work as you might damage parts, once it's cleaned up then you will be able to see what is needed if anything.