a grulla is a black horse with one cream gene, a perlino is with two, Your horse appears to be a grulla with the dun factors, the dun gene gives the horse a some or all of the "dun factors" which are ear stripes, zebra stripes, leg barring, the black lines across their withers and the dorsal stripe, the guard hairs on the tail and white hairs on mane, it is not considered a dun unless it has a dorsal nor if the dorsal fades in the summer, a dun must always have a dorsal no matter if red or black or bay. A buckskin is a bay with the cream gene, but there can also be a dun-skin and that is a buckskin that have 'dun's' in their parent history and they express the dun gene through the "dun factors"....clear as mud right???
A grulla does NOT carry cream. It's Black + Dun.
Perlino is Bay + 2 Cream Genes.
Smokey Black is Black + 1 Cream Gene.