You don't restore these older games because it's "worth it", you do it because YOU want to and you love the game! I don't think you'll get your money back on just about any older Bally/Williams restoration from the 80s.
That being said, I'd be more than happier to take the Medusa off your hands if you are willing to ship it!
To me, the game is totally worth a high end restore. Your results/opinions may vary.