I think this one was the day he was born or a few days after, this doesn't show it real well but:
You can see the original smudges there and they were GOLD, as gold-yellow as my palomino mare is.
This picture shows the gold-ness of them better, I believe this picture was taken at about 1month old, maybe 2 months. It also shows his typical coloring, which is what makes me think he's bay.
And then a month later, the gold smudges had started to lighten and spread/roan out away from the original marks.
This was a few months after the last picture:
End of that same month: (you can still see some of the gold coloring under the white-silver color)
And then this one was from earlier this month.
I figured there's always the chance it's just some odd bit of sabino too, but I'm hoping it might be something more interesting at the same time. XD