I just looked on eBay, sold listings, one sold for $2124, another for $4500. You can buy a nice caddy convertible for $10k. I would guess $10k for the one you'll be selling would be tough to achieve. Cost to paint a car like that is $2k to $5k, interior would easily be $2k to $3k, vinyl top $1k. Given the described condition, they'd be lucky to get $1k or $2k.
YMMV.
YMMV.