Thanks for the reply. I think I had the rare luck of getting a diamond in disguise. The exterior looked terrible but the interior looked like it was 1983 still. Hardly any dust and no wear and tear on any of the parts after I cleaned up the keybed contacts and buttons and it worked like it was 1983 too. I think I got that one synth someone brought, never played and chucked into storage only to be found years later.

The top panel is the only piece that tells the story of how long it's been sitting around but I'm grateful I didn't pay too much for it and got a great keyboard.