Yes, they do, but if she is a product of a Black Copper parent(s), she carries the copper gene whether she expresses it or not. I have had a few hens here that did not show any copper at all until after their adult molt at about a year of age. A pure Black is very hard to come by, just because she may show pure black, doesn't mean she is one. I think your gal is fine, and right on target for her age.