Is the 25 ft. Aluminum Roll Valley Flashing already clear coated to protect against corrosion?

Aluminum normally does not have a coating over it.

Aluminum normally does not have a coating over it because aluminum is considered resistant to corrosion. This is because of the fact that rust is iron oxide, and most aluminum has almost no iron in it. But aluminum does oxidize and it actually protects the underlying aluminum material, which is why its popular for outdoor applications.