Streamers don’t come in till then yes. Just in my experience the length of the crest feathers and the stance of the bird were the most reliable method for sexing at this age. Not 100% obviously. Just my own experience.
Yes they get streamers at a later date. I just know during my time breeding these guys, that the length of the head feathers and the stance of the bird at this age was more reliable than comb or other tricks people use too tell. Not 100% obviously. Just little things I noticed.
It’s the head feathers that make me think roo. Roos have longer messier head feathers at this age, for the most part. But if you have a boy and a girl you can have silky babies :)