No, it is not 100 percent reliable as a chick, talking about eyeliners and V's on their heads.The probablity of males and females by observing the V's and eyeliners are a bit higher. Some lines are better than others.
If you are talking about the length of wing feathers, no......
As the chick turns into a young adult, the differences between the males and females are different and you can tell them apart from males and females.