Help me ID the coating, AA floor pans Options

[Superhawk996]

Have a mystery on my hands.

I ordered both floor pans from AA. Ordered within a couple months of each other back around August 2018.

Floor pan on the right is clearly Galvanneal -- uniform grey coating of zinc that is annealed into the sheetmetal. Doesn't rust when left exposed or where it has localized scratches to bare metal. You'll notice on bottom of right side panel there is a little primer mist over the seat brackets, seat reinforcements, and the pedal box reinforcement where the parts were spot welded together. This makes sense to protect the welds from rusting in storage.




Floorpan on left was shipped with light coating of primer over 100% of both sides of the panel. I set them aside not paying much attention. Now that I'm getting ready to install I've noticed some differences.

The primer is laquer based and needs to be removed before I primer with 2K Epoxy. Upon removing the primer the metal is mottled in appearance.



Some sections are clearly coated 100% (with something) while other areas are mostly uncoated. Under the primer i've found the start of very, very minor surface rust. Not huge amounts, but enough that it makes no sense to prime these without 1st treating with Ospho to remove the surface rust. Painting over rust never makes sense. The coating is clearly not zinc based otherwise the surface rust wouldn't be there and the zinc would be serving as the sacrificial annode. So not Galvanneal and not Galvanized.



So the mystery is what is the coating? I think it is some sort of aluminized steel. It's definately not paint and seems to be metalurgically bonded to the steel but yet offers no corrosion protection to the exposed mottled surface. Any other guesses?