Yeah, it's tough to tell in that pic if he's agouti or something like tort. Do the hairs have black tips? Or do they seem to be mostly one color over the whole hair?
He does look like a sable chin. If you blow into his hair, you should see a distinct white band on the hair, then a black tip. Those bands of color are what make him a part of the agouti color family. The white belly also is an agouti trait.