sex linked chicks

I was reading an old book and it explained that by crossing a 'golden' cockerel with a 'silver' hen you got chicks where male and female were diffrent from hatching.One of the hen breeds it listed was silver dorking.I'm sorry for being stupid but does that include silver gray dorking or is it a diffrent breed?

One of the 'golden' cockerels was rhode island red.I was thinking of getting a buff orpington cockerel which I would imagine to be more golden then RIR.Will I get sex linked chicks by crossing a buff orpington cockerel with a silver grey dorking hen?(Come to think of it aren't dorking chicks sex quite distinguishable when quite young anyway?)