The straw color in his hackles mostly likely is caused by : 1. he carries a silver and a gold gene 2. he may also be heterozygous (split) at the E locus.
If he has some characteristic that is exceptional, I would go ahead and breed him. If he is ho hum, then keep him as a pet.
The buff color is due to four or more genes. It is a polygenic trait, caused by many genes, so it does not fall into the recessive or dominant category.
If you want to produce black chicks from barred birds, cross a barred female with a black male. The male offspring will be barred but the female offspring will be solid black.
Tim