Coupla hundred max! It's not worth restoring if you were wanting a bike to put away as an investment when they become rare (in 50 years). For $1500 you could get one in good condition that would be easy to restore.
As Brock says, strictly for spares, and then all the exposed ones are badly weathered (switch blocks, for example). Only worth storing if you have excess shed space. One day the engine, drive train and rims will be useful to someone.