That certainly is interesting. My first thought was OMG that horse is giraffe colored! But it looks close to a pattern that's seen with traditionally with dapple grays, it's just that this horse has a chestnut base as opposed to a black one.
I'm interested to hear what others think though. It's definitely a horse of a different color
FYI the Craigslist ad states that the horse is a papered saddlebred.
In the picture of the black based grey that Ink shared, the white areas are the circle parts of the dapple pattern with the dark body hairs making a lace pattern. The chestnut has what appears to be a white lace pattern over the entire body. What interests me the most is how the face is colored. That isn't a normal coloring, especially when you look at what happens up by the forelock. Compare that to a giraffe, I don't think this is a roan or a grey. IMO