They definately have the look of Altamonts. That particular scrimshaw design is not in Altamont's current online catalog, but Altamont is famous for doing special runs for distributors and large grip dealers. They are unusual and prolly valuable beyond normal more common grips of like kind.
Most all of Altamonts stuff is CNC machined and or laser etched/engraved, so it's simply a matter of writing a program rather than employing a master craftsman. Not to say that Altamont stuff is second rate, their stuff is top notch and quality is superb while keeping costs low.