When we are on http://kingdomcomerpg.com/, we can see one horseman and many bodies. But there are also two Silesian flags. Does that mean we will be able to travel to Silesia? Most of that territory was in Bohemia then, and rest was vassals of Bohemia.
The first act takes place in Bohemia, around Rataje village. AFAIK locations of other two acts haven’t been revealed yet. So it’s possible, but definitely not in the act 1. However, it’s very likely there will be some Silesian nobility or soldiers.