When he said carbon fibre, he was probably thinking of matte black, which looks a bit like carbon fibre. I'm pretty sure he doesn't mean we can actually have a paint chip of carbon fibre texture. But yeah, he was just talking about the paintchips from the DLC, which opens up to a whole different range of colors you can put on your cars.
Anyway, I'm personally glad that it's cleared up about the whole DLC decision thing, and what should be saved for GT6. Also, it implies that IF GT6 does make it to the PS4, the premium cars that are already modeled can be carried over easily from the fact that all it is is marketing decision to decide which goes to GT5 DLC and GT6, although most of us already assumed that lol.