Have a question regarding the paint color that Porsche used on the inside of their rims.

I am in the process of refinishing a set of C4S wheels and I noticed that the inside of the wheel is a light grey color as apposed to the same color that is sprayed on the face (outside) of the wheels.

Does anyone know what color this is?

Thanks...

 

Which C4S wheel? My technos seem to be the same color...