Without knowing the exact metal of the screws, what sort of materials (salt spray?) it was exposed to , etc. we can't say for absolute certain that the rust couldn't have happened quickly. Common senses, however, says that your suspicions are much more likely to be true. Perhaps you could somehow get the dealer to give you some of those screws. Then you could test if there's any reasonable way for them to have rusted so quickly.
Mike W.
(published on 05/19/2017)
