Wow, they DO look alike - comb/wattles and tail feathers that point upwards! Spaceship is such a sweetheart, I hope he'll be a kind rooster. It is a bummer though - especially since you only have 3 chicks!
I have 5 chicks that 4-5 weeks old. I suspect that the astralorp and one of the barred rocks are cockerels and the RIR/Golden Comets and the other barred rock are pullets but I'd love some expert opinions.
Astralorp (Spaceship)
Barred rock 1 (Dave)
Barred rock 2 (Bird Person)...