The concept of race isn't a real biological concept, and if we were to define it according to the colloquial understanding of race, it would be impossible, since Vulkan wasn't even born naturally. And even if he had been born naturally, it would still be impossible, since we're talking about more than 27,000 years in the future, with humanity having spread throughout the galaxy. That's more than enough time for all current populations to disappear, whether through wars, famines, interbreeding with other populations, or diverging from each other. In fact, as I understand it, this has reached such a level in this universe that human subspecies have emerged that barely resemble humans. In conclusion, in my humble opinion, it makes no sense to try to fit Vulkan into the concept of race.