They announced this during the keynote ("two-tone"). It wasn't very stealth.
The website also says they are using a new calf leather, and they have that new cut along the edge.
I always thought the old classic buckle leather was cheap looking/feeling. IIRC, they are using the ECCO tannery, which isn't a really upscale leather supplier. Hope the new calf looks/feels nicer.
The new Saddle color is already something that I want. I was surprised a nice brown leather strap was missing from Apple's original offering. Hope they rounded off the edges on the keeper. That thing always dug into my skin on the original BCB .