BioEditDuring the Clone Wars Era, each Clone or Clone Trooper had their own personality and traits to distinguish themselves from one another. They often have customized armor, combat skills, and different hairstyles. As well as having different facial features. Such as: tattoos, scars, and cybornetic eyes.
It wasn't Anakin Skywalker first met ARC Lieutenant Alpha 17 during the battle of Jambiim, that he would actually nickname THE very first Clone and create a much more organized strategy for squads and battalions for the Republic. As well as allowing Clones to express themselves more, rather than being used like average droids.
Commander Cody was the first official Clone to be nicknamed throughout the Star Wars franchise, but ARC Lieutenant Alpha was the very first Clone to be named chronological-wise.
Officers are the only Clone Troopers who customized their armor, to whom they were the only ones permitted to do so to help avoid confusion.