Yes, I believe that the roof running board is injection-molded styrene and the brake wheel platform is stainless steel etching. While plastic is more fragile than metal, it won't warp and pop-off and it is more paint-friendly (and can be molded in color, like the rest of the car, before being painted). But it is thicker than the etched metal, and the grid pattern is probably a bit more coarse than equivalent etched item.
