I can't say anything about Bohemia specifically, but I can tell you that we wouldn't necessarily read the Moors as "black". The Spanish Moors were of Arab, indigenous Iberian, and Berber descent. Many (but not necessarily all) of those people would be read today as "white". Look at, for instance, the French soccer player of Algerian Berber descent, Zinedine Zidane. Look at contemporary pictures of the Berber emissary to England painted right at the transition between the 15th and 16th centuries. Look at this 13th Century Iberian manuscript illumination of Moors. None of them we'd necessarily call today particularly "dark-skinned".

I have a longer post about the "social construction" of race, specifically using Arabs as an example, which you can find here that I think is a good introduction to understanding how racial categories are inconsistent and subjective. This is not to say that Moors were white or not white, but simply to emphasize that the boundaries of races are contextual and culturally specific. President Obama is Black in America (despite being, ancestrally, half Whire and half Black), but in Brazil he probably would be Brown (Pardo) rather Black (Preto) by a large portion of the population. Here's a quote from a Brazilian political scientist about race in Brazil (full interview):

Q: How is the concept of race different in Brazil compared to the United States?

A: The difference is that in the United States racial classifications were based on a legal definition that said if one-eighth of someone’s blood was black, then that person was considered black. Many people who are considered black in the United States would be considered brown, or light brown, here in Brazil. Not necessarily black as such. This has created divisions among ourselves, which has made it difficult to mobilize and organize black movements.

B: What about Obama? Would he be considered black?

A: In some circles, yes, and in others, no -- he would be considered mulatto, mostly because he is elegant, educated and well-off economically, that is, all things that are associated in Brazil with being white.

However, while today many of Moors would be seen as at least phenotypicly White, at the time in many places they were seen as a (often imaginary) Other. After the Reconquista, many high class Spaniards were fixated with the idea of limpieza de sangre ("blood purity"), that is, having an ancestry free of Muslims and Jews. Anthony Marx, in Faith in Nation, argues that this is systematic exclusion based on ancestry is one of the first stirrings of modern nationalism, and it also helped set the stage for European conquerors' very ethnicized/racialized policies in the New World.

The Moor, in this later context, gradually became imagined as darker, more foreign looking. Even on the Wikipedia page linked in that discussion, you'll notice that Late Medieval manuscript illuminations literally paint the Moors as fairly phenotypically white looking, while Early Modern illustrations (presumably under the influence of the burgeoning African slave trade, but I can't say for sure are more likely to show Moors as phenotypically "black looking".

Would it surprise me if there were a few "Moors" or other non-Europeans in Central Europe here and there in the 15th century? Not at all. The Ottomans, of course, were in Central Europe by the 15th century (they laid siege to Vienna in 1542 and the Ottoman Wars with Hungary began in 1366). I'm not exactly sure how Ottoman trade worked at the Empire's expanding northern frontier, but, I mean, it's hard to imagine that "zero" Ottomans went beyond the borders of the Empire. But, today, we probably wouldn't recognize most Ottomans and Moors as "Black" (though I don't know, there could be some), and I'm not sure at the time the differences between, say, Ottomans and Hungarians were necessarily seen in primarily racial terms (that is, social categories connected to phenotypical appearance, especially skin color), rather than cultural, religious, and "civilizational" ones.

What I'm curious about, though, is whether the game included the more local "Other" of Jews, who existed in large numbers in Central Europe at the time, since at the time religion, rather than race, was one of the primary organizers of social difference in Europe, the Middle East, and North Africa. Looking at sometimes weird discussions on the game's message boards suggests not, but there is at least the possibility that they, or other potentially non-Christian groups like Romanis or Turks or Baltic Pagans might appear.