My friend Dennis (Demo) gifted this to me a while back, and finally got around to restoring it (thanks again Dennis). After some research I found out it is a WW2 "shark" knife as it was carried by Naval Aviators. Western made several styles of it but all with the fuller groove. Had to put new leather handle on it and grind out what looks like someone's attempt to remove rust with a bench grinder. Acid treated blade as per original finish. Made the sheath for it. It will go to my brother in law who collects Westerns.