Our girls didn't settle into their true color till after the shedding of their 2nd year.
Saro went through so many really odd color changes I thought sometimes she would be the color of a giraffe complete with spots. All of our dark horses fad considerably by mid to late summer. Vida who is jet black in spring will go a red color. If I don't wipe the sweat off after a ride, she gets a red saddle on her back that looks really odd. I always have the vet put "faded black" on her health papers that we travel with so if we have to show them they will believe she is mine.