No, they didn't get their sleeper ship. Too bad. But yes, they're there. If you mean, "oh hey well why isn't anyone RPing a black char?" well, some are actually.
Whenever this topic pops up, people usually mention Orillion.
But I rarely see people mention Sinclair. Remember her?
But yes, everything in Freelancer is pretty stereotypical in terms of ethnicity. It would appear at first glance that the original developers didn't put much work into making the houses of Sirius culturally diverse, but if you look around long enough in the bars, you'll find a few non-white (or non-Asian, in the case of Kusari) NPCs. Not many, but a few.
There's no real canonical source stating that people of African descent don't exist in Sirius, though, so feel free to roleplay one if you like.