What does it really matter? Egypt is a north african territory so the people who live there even those who lived there 4000 years ago are more lilely bronze skin coloured like every other north african.

Dark skinned people are from central and southern africa. I think that answers your question, however it is possible and very likely there were people with darker skin in ancient Egypt. This, I think, would have been nothing outstanding because even in that age or especially then people moved from their native lands to other places.

And finally, since the Egyptian kingdom of old was a rich nation it would naturally appeal to people living in poorer lands.