This has been a problem since the inception of this S197 body.
Hood is aluminum and normally will show corrosion underneath front edge of itself first.
Trunk is made of steel, in salt air, or salted streets, lower inside lip of itself may show rust, as paint is thin near seam and sealer at seam.
Not clear where this car is located, parked most of the time. If within 1/2 mile of the ocean air, it very likely could show damage within a year.
Orange spots on other car, most likely industrial fallout from a manufacturing facility or any chimney exhaust..which has in it metal or chemicals.