Sabino ticking? Or...?

My Spanish Mustang colt will be 2 in a couple weeks, and he's just aaalmost finished shedding. He has several white hairs on his withers and rump, and some extending down behind his flanks. When he shed last year, he only had a couple hairs on his withers and maybe 2 on his rump. His only other white is star. His dam has the sabino ticking in all her colored areas, with one actual "roan" looking area on her right hind below the hock. So would this be sabino ticking/roaning that he has coming in? Or something else? I will get pics as soon as he's completely shed off.