I have a brown board as well... Felt really bad about it in the beginning, truth be told, but I'll be buggered if I can notice it's color behind the 310mm gpu and the Noctua D14 and all other sh... Not to mention, the window of my case is smoked, so the colors are even more darkened, and the lack of lights helps... It's brown. It doesn't matter it's brown, but the answer to the question is Yes, it's brown...
Yeah I wish I saw this before I ordered it but oh well, none of the pictures or YouTube videos show it being brown. Maybe the direction you look at it affects the colour you see, Hopefully in my r5 it will look black through the window but will have to see. There will be a GTX 980 ti FTW Gpu on it and a h100i GTX which will cover most of it so I should be fine...Hindsight I guess