They are actual metal. You could probably apply them yourself...I would assume it just needs a clean surface and has an adhesive backing to them.
I always thought to myself 'what kind of idiot wastes their money on something like that,' then saw them on a Corolla at the NY auto show and bought them with my new Corolla. They were shiny and I wanted them dammit! Hopefully the image below comes through. Those are the front. The rears are shorter due to the much smaller door sill.