Is barred black sexlink always a roo?

[Frazzemrat1]

What makes a black sex link work is genetics. Black sex links are created by using a red rooster over a barred female. What happens is that the barred female can only pass her barring gene onto her sons. Its impossible for her to pass the gene onto her daughters. Thus, at hatch, her daughters will be black and her sons will be black with a white dot on the back of their head. As they mature, the females will be black with a red breast and hackle, the males will be barred.

I believe the bird in question is a cockerel... In some of the pics I swear I see saddle feathers, but not a lot of them. He's just slow to mature.