From what I understand, the roos without the black are showing the columbian gene which is restricting it. If your pullets have the black, then it may not matter which roo you keep... but I wouldn't want to get rid of the dark one.. just in case.
I had a dark one like that (the darker ones seem to have better type as well) and ditched him early on. I was lucky enough to hatch another recently from Lynne's eggs. My hens with excellent background color are all lacking the chevrons so, now I realize how important the darker ones are.
My pullets like Bluffcountry's, Java would not benefit so much from him so I have a lighter one just for that scenario.
Equibling, I really think you should keep two roos at least for genetic diversity.. and may as well have them different so you're not betting everything on black... you know.