Markings on Weaver J4 scope

I have a new, (to me) Weaver J4 scope from the late thirties, early forties, with Redfield Junior 3/4" rings on it. The question is this; What,(if anything) do the "L" and the "S inside a diamond" signify? This is a nice small diameter 4x scope and I like that. It is functionally similar to a Lyman Alaskan in that it is fixed power with long non critical eye relief, adjustment knob caps, and it's small and light yet tough as a piece of water pipe. I'm just curious about those markings.
Thanks!