Danny if your really concerned with rust, go to your local auto parts store, purchase a (various names) metal thickness pen, body pen, magnetic pen, they should come with a gauge that reveals the thickness of the metal. If it has a lot of randomness there is probably rust/bondo under the paint. Make sure the frame rails are strong and rust free. I have learned the hard way to alway carry one of these pens and a good awl before buying a car. Use the awl to tap the rails up and down and do it hard. If the awl goes through your rails have problems that are fixable but very expensive.

Good luck, they are fun cars.

-Erik