Michel we have been Aluminum plating the back side of fiberglass cobra hood for many years and yes its real aluminum so it will need to be polished every now and then. If you’re trying to keep your cobra period correct I do believe that the scoop was black painted fiberglass. If you want the scoop aluminum you could just have us Aluminum plated the back side of your scoop, doing this ensures the fit to your hood since it’s the one you will be removing. Just a thought.
Ron