He will definitely provide a brown egg gene to his offspring. They will likely be good layers, although not the egg laying machines that first generation Sex Links are. Because Sex Links are hybrids, they will not breed true and even breeding two Black Sex Links together will not produce a Black...
I thought I was seeing that correctly. That rust/copper color on a Barred Cockerel is indicative of a Black Sex Link rooster. It is a product of the red gene rooster that is crossed with a barred hen to produce Black Sex Links.
You're welcome; and you're right about the yellow legs. My reason for thinking he may be a Black Sex Link is that when it look at him (granted the lighting is rather dark in the pic), he appears to have traces of rust, copper, or reddish color in his barred feathering, particularly in the wing...