I know this is a crappy picture, because my phone lense is scratched on one side but it's the horse I was referring to and a good comparison of black and brown. LOL
All three of these are branded mustangs. The "dead" (lol) one and the one on the left are both brown geldings (notice the muzzles and flanks). The filly on the right is black. The dead one is the one who currently has the golden dapples coming in on his girth.
The one on the ground is odd because he has the mane of a curly horse LOL
Also your horses dorsal stripe might just be counter shading.