John, not to break your heart or anything... , but I've got one just like that in a fencerow on the farm I've hunted for years. While it may indeed have been made by one large buck, the one on "my" property is a "community rub"... It gets hit by every buck that crosses through cutting from one field to another, and it's just widened and widened out over the years. It looks to be almost the same size as that one.

Hope I'm wrong, and it's one heckuva bruiser for you... or maybe two, or three...

Just food for thought.