Muslims come in all colors, and some wear those white touqes that look like a skull cap. "Muslim" is a member of the Islamic religion, not a race. Just like a "Christian" is a follower of Christ's Gospel.
Agreed, which is precisely why I asked about the head covering. A Yarmuka or a Kufi would mean that the person is self labeling as a member of a particular group.
I would give long odds on one, and strongly suspect the other.