Looks like a shiny coat/healthy horse. 2 of my bays and all of my sorrels dapple - no gray. I'd say what you are seeing is light reflecting. Looks like what I've seen of horses I have been told had a galustra plume.
Those are both really pretty and very neat looking. The Arabian is greying, and as for the 'plume' vs sabino (?) I think that's what one post stated, guess no one will no for sure until it is Tested..
All I know is it neat.