My last two buff orpingtons developed combs differently - and one always remained a little paler/smaller; My current Buff's are about 6 week old - they so far look like hens to me (and don't look too much different from yours - just bigger).
Looks like my two (supposed roo's) Haha I'll post a pick of them at that age and you can see the difference in their color and their combs~ The lightest one is Princess for sure a girl. Yours also has the wattles turning red already. My guess is roo! Look at my pics and you tell me