If the yare only 2 weeks old, it's too soon to tell. They should all look like that right now. You should be able to tell about 3-4 weeks, the females will still look like that, and the males will have breast feathers that are totally red (orange), with no spots on them.
Now The adventure begins trying to sex 19 button quail and keep track of who is what color and of that color who is what sex , trying to tell them apart will be hard for me at first . Is there any way to mark them with a number and keep info in a note book like I do with eggs? and how do a lable them with a number, do I take a sharpie and try to find a spot on them or do I make a leg band and have 19 colors and use a number for eatch color , this makes my head hurt just contemplating it