Are they called anything else where you are? Some other common names here are goosegrass, and the best - sticky willies.
I'll be pretty surprised if I'm wrong. His barring is darker than the other Barred Rock cockerel from that hatch but lighter than the pullet's. His wattles, comb and face are more red and wattles are more developed than the pullet's, although again not as much as the other cockerel (who's also bigger and took less time to grow all his feathers). The pullet has a dark wash down her legs while the other two's legs are almost completely yellow, and she also had darker down and a neater head spot when she hatched. Much more chest-bumping between the two I think are cockerels as well.
They're 8½ weeks old now. I'll try to get photos of all three of them for comparison tomorrow.