Quoted from vid1900:Keep the game, fix it up.
Many NIB machines will have some corrosion if they were stored in an unconditioned space.
Yeah I got screwed over same as you on this WCS I'm remaking. Guy told me that the game had just gone through a shop job with one cracked plastic, no cracked ramps and had no hacks. Game arrived with 70's style bally legs, no speaker panel, electrical tape holding wires everywhere, screws in playfield etc. So I'm fixing it up and brining it back to it's former glory. I seriously think the guy gave me fake pics. I'm in Canada, he's in Virginia = I'm screwed.
Quoted from Rum-Z:Can you just restore and shine the metal parts on top of the playfield and make do with some less than stellar quality metal on the bottom side?
When you start taking everything off the top you might as well take everything off the bottom.
To answer your question. It does not depreciate value. This seller just doesn't want the game back because he knows exactly what he sold you and he'll find any excuse in the book.