From the picture, it does look to me as though she has some brown tones to her head (the picture or my computer could be misleading, though). One thing about the coloring on the rest of the body: one of my boys, Jack, is black and white, but the undercoat on his body is that same mahogany as your girl. Although on your dog, it does seem as though it is definitely a reddish-brown, no black. Does she have any black in her body coat? What color is her nose? That is usually an indicator of coloring. Interesting, but still beautiful!
Her head and tail are darker, with some brown mixed-in. There's a breeder/boys' home hereabouts that comes up with a gorgeous shade of chocolate brown -- one shelter boy I think may have been born there was so strikingly handsome I just had to name him Clooney. I may check-in with them about Mocha, as well, although they had no recollection of Clooney.
Thanks again, everybody -- big help!