462 is what we call a "Marrow Spoon". Used when fly fishing. When you catch your first fish this is put down the fishes throat into its stomach and used to scoop out the contents so they can be examined, so you can determine what the fish have been mainly feeding on. Then you can tie on a suitable fly/lure to enable you to catch more fish. (The difficult bit is catching the first one!)
Regards from Glenrothes, Scotland
Michael Amateur Woodworker and Part Time Fly Fisherman!