Klasse AIO was made for that car. It'll remove the oxidation chemically and reveal the real paint under the oxidized layer. You'll have to put a sealer of choice on top of the restored paint or the oxidation will return really quickly.
Klasse offers their Sealant Glaze. The AIO and the Glaze are referred to as the Klasse Twins but it's not essential you use the Klasse sealant - there are quite a few other sealant choices that'll work too.
So, get the car and negotiate a price based on the bad paint. Don't reveal your secret weapon - Klasse AIO.
-John C.