The seller is the LAST person on earth that will give you an unbiased answer to that question. You have to have the car inspected prior to purchse. Don't even consider not doing it.
'60s cars, not just Camaros, were not well made to begin with and were never intended to last 45 years. Perforation of body panels is the least of the rust concerns; structural components such as frame rails, floor, roof and cowl panels are common rust areas on Camaros. They are often patched up enough so as not to be obvious and the owner may not be aware of prior poor repairs. The car needs to be thoroughly inspected on a lift by someone who knows where to look and what to look for. Pictures won't get the job done.