It's a bit early to tell if he'll be gray. If you start to see white hairs starting to come around his eyes then he will most likely get grey like his mom.
We too just had a colt born about 2 weeks ago from a maiden 30" mare. We had ben watching her on the monitor ...eating hay and nothing unusual and all of a sudden she laid down and started pushin. When we got out to the barn the little feet and nose were already and just a couple more pushes , he was there! Never seen one come so fast...shows that even those little ones can do just great if the foal is in the right position. Love those fast ones! Mary