His dorsal stripe isn't dark. 3 of his 4 legs are black though I don't know how well you can see it in the pics. I am sure they will show once he loses the baby hair. One is white. Its hard to tell how much is white but I didn't see any black on that leg. I don't think he has any other white on him. Except his lip looks like maybe he will have a small spot.
Since 1987 the AQHA has classified a horse with a dorsal stripe as a dun and a horse without the dorsal stripe as a buckskin. So with that being said he would have to be a dun. I am so not a color person.