Yes you hit the age exact These are sagitta chickens, they are super sweet and already have feathers on their head.
My boys have comb ridges, since 2 weeks old... it's hard to tell, but I don't see ridges here...
My girls had combs early on. I just know when someone usually spots a roo, their combs and wattles grow leaps and bounds faster than any pullet.
The Sagitta look a lot like my Red Star. And boy do they kick their growth into overdrive around that age. My babies will be 7 weeks old on Friday and they're so huge! They're so much fun, I love them!