He didn't look black in the film to me, looked like a darker brown. Anyways, it's impossible to say what his skin tone was but judging by my own fathers appearance as well as my ancestors who are Sephardic Jews with ancestry to Algeria and the Middle East, I would say that he and the ancient Israelites were likely anywhere from lighter skinned (in the northern regions) to an olive skintone (ranging from medium complexions to darker complexions), Any darker is probably going to be from the Arabian peninsula as the people there are much darker than those of the Levant.
Anyways, I suppose it's possible Moses was as dark as featured in the film, mediterranean peoples can get pretty dark if they tan from the sun. On the other hand, take them out of the sun and they can get pretty pale.