Oh my gosh, I just LOVE her butt!!! Cutest butt ever!
I will not even guess on the gray/vs. not because her legs are white, and for me that is the easiest indicator to see gray. I have a gray colt that was NOT born with white goggles or even a single white hair around his eyes at all. He's only now starting to get goggles at age 3-4. So I would entirely believe it's possible for her to be gray and it not show around her eyes.
So I think you have a 50/50 chance of her being gray, how's that for a safe bet.
Anyway, she has the most beautiful markings on her rump and tail! I love her!