Really? Which ones? Postwar?
EDIT: Belay that. I just checked a few. Found it in the 1951. I don't ever remember seeing one in any earlier cats, but I checked the 1933, 1939, 1941, and 1946 just to be sure. It's not in those, unless I missed it. The branding on the tool in the 1951 cat looks like the Bonney marking with the slightly larger B and Y. Yours could be later, but who knows. My Reiff & Nestors and my Blue-Point (made by R&N) are all wartime or earlier, but R&N made them for a long time, and then JAW appropriated the design and made a crapload of them, too.