Vintage dial question

[KZZN]

Hi,

Here's a question that floats into my mind every so often. On some vintage dials (I think I've only ever seen this with Cellini models where Rolex is concerned), the usual blurb at the bottom of the dial reads "SWISS", but is surrounded on either side by what I can only describe as a symbol that looks like a capital letter Q that's gone through a three-quarters clockwise turn (so like an O with a diagonal line sticking out the top-right, basically).

Can anyone shed any light on what this symbol means, or what this particular dial signature signifies? I've seen it with other brands too over the years very occasionally, mainly JLC and Patek I think. So I don't think it has a Rolex-specific meaning. But I've got no clue myself what it does mean.

Thanks in advance to anyone who can help!