If they are anything like the Whyte carbon, it's a coating. It's not great, but if you shoot with a glove normally, it's not horrible either. It's basically the same thing as the "wood grain" CF shafts on Aliexpress.The Becue original white shafts were cosmetically perfect, but the finish requires that you wear a glove.
There's a company called Proqure that has different colored "carbon", but I couldn't get a straight answer out of them if it's a coating or not, so I'd say it most likely is. I'd be happy to be wrong though.
I'd love for a company to come up with a method or formulation to tint or color carbon fiber. I'd be interested to see if something like a graphene sheet could be colored and roll or filament wind a shell over a quality CF shaft.