[frontierrots]

He's black & rust. His face would have to be lighter to be a black & tan

The extra tan on his throat is a "double mark" or a "necklace mark" It's usually called a necklace mark if it's a thin line like a necklace, so I'd call his a double mark. Some double marks shed out but since he's over 6 months old I guess it will stay. Double marks are fairly common in some lines and is a color fault if you were showing him