Fab. Suisse caseback help, please

Dear OF-ers, I have a beautiful Cal 360* "extra-plat"-powered dress watch from 1949. The case is unusual and the dial is clearly marked "Fab. Suisse", so I have always assumed it was an export to France, but getting the caseback off has proved a job exclusively for the professionals. My watchmaker has now managed to do this, and given me the following picture. For my education, please, can any experts here tell me anything that this does or doesn't say about the watch? 📖

In advance, thank you! 😀
*Btw I come across mentions of this cal very seldom, even though a fair number were made. Anything I should infer from that? 😒

Can you provide some closeups of those hallmarks?
You likely have a French-cased watch. Some threads here might be useful to you:
https://omegaforums.net/threads/french-gold-cases-marked-“pgf”.64734/
https://omegaforums.net/threads/french-omegas-and-their-numbers-looking-for-info.53549/

Looks like exactly what you though it was from the dial.

The older Omega "garter" logo was used on French made 18K gold cases in the 1940's and '50's. The initials in the lozenge is the maker's mark for the case. The serial numbers were generally (but not always) in line with the Swiss made cases. 10.8M would be consistent with early 1950's.

Hope this helps,
gatorcpa

Thanks for those links - appreciated. Here is (I hope) my max magnification of the marks in there - steam now coming out of my computer...

I'm grateful to @gatorcpa for his obs too - although I don't think my eyes are going to be able to resolve the initials that quickly, so any experts to whom this is a piece of cake, please just weigh straight in!

Well, I reckon it's our ami "PGF" again alright - but maybe I need to take a bit longer researching who that might be, because the Googleverse isn't providing any instant answers on that just now. Thanks again to all for your help.
PS is Cal 360 unloved? Or just a bit off the beaten track?