No gaskets from factory. It's not metal to metal. The surfaces are painted so it's protected. More so if epoxy was use prior to paint as it should have been. My car and others see mother nature often and I have zero rust issues in that area. Any bracket bolted tightly to a painted body panel is going to ruin the paint to some degree. But if the paint integrity is not compromised to expose bare metal, corrosion is of no concern.
