LGpCd'Oex is a pretty good guess, as there is/was a Les Granges village in the municipality of Chateau d'Oex.
Pointing me toward Les Brioux got me a map that showed Bas-des-Brioux as a thoroughfare there and so the postmark apparently was that of a post office lovcated on that road. Vayolene has a good point about the spacing on my stamp as being suspect.
Thank you both for your assistance.
