There is a color which you hardly ever see any more in Dobermans which is almost liver--in bad lighting you'd have a hard time deciding if the dog was brown/red or black. The nose is brown in these dogs.
Judy Doniere, a doberman breeder/judge and I have both seen these dogs--they are characterized not just by the dark coat color but by an extremely wirey coat (not just harsh--which is correct but like a terrier, wirey feeling coat), usually the markings are straw and the eye is inevitably yellow.
I suspect that that particular coat and color was selected against since it is incorrect in so many respects but the color is very very dark--a dark brown mahogany. It's usually dull as well which seems to be a side effect of the coat texture.
I haven't actually seen a Dobe in this color since the late 70's.
I expect what you saw is just one of the many variations on the Dobe brown/red--people like to give inventive names to colors--I've heard the lighter red color referred to as copper penny red.