Carbon Fibre bonnets in real life doesnt necessarily have to be black. they can be painted over or laqured over with gloss. But usually, most just leave it black. It is actually not totally black. It is a mesh woven design that has black and tiny silver colour in it. Looks good as it is.
Also, due to the light weight of the bonnet, high speeds on occasion may unlatch the bonnet and so people use bonnet pins to secure the bonnet in place on top of the standard bonnet latch that the car already provide.
Bonnet pins can be attached to any type of bonnet not necesarily have to be made of carbon fibre.
Cars with bonnet pins now a days you see in the street are probably more for cosmetic (ie: look nice) rather than truly functional usage. because you will have to be doing 200+kph (or even more) and taking corners at serious G forces before your bonnet can unlatch from the windforce and G forces.
