Was reading your tags. As far as color goes, I’ve seen several so dark I thought they were black at first. And then they got into the light and the lighter shade showed up. Unfortuanetly it wasn’t particularly sunny when I got my photos of him. So I can’t remember if I saw any slightly lighter spots. But good chance that was just timing for me. Since if you’ve seen brown spots in other photos then he probably is just an extremely dark bay/brown.
That being said I have seen horses registered wrong before. Multiplier was registered as a bay/brown colt Preakness last year. Despite the fact it now says he’s grey. Which yeah he definitely is.
So they don’t always get it right