Definitely could have been a mellanistic deer (extra dark pigmentation in the coat.) Or, it could be an old bugger. AT out camp, we have seen the same fork horn for three years now. His coat is not dark like the one you saw, rather his coat is very red, almost as if he doesn't lose his summer coat. His rack has not changed though in three years. He is about 14" wide, but with only one tine on each beam. His name, of course, is "Red."