Hello guys,
After looking in my references, it turns out that a "canon monobloc" means that the entire assembly is built in one hunk of steel: both barrels, lumps, and maybe even the ribs.
This explains why there is no sleeve mark on that barrel set.
The English "monoblock" is "frette" in French and is totally different of course.
A one piece barrel set would be very difficult to do, especially back then.
Jean Breuil was known to do this.
I did not quite expect this but the French tradition is for the barrel maker to make the entire assembly, and not just the tubes. The Bernard thread is another indication of that.
Heurtier was silver soldering the tubes together, so he was building sets and not tubes as well.
Quite interesting...
The double R mark which is carbon copy of the Rigby trademark is still a major mystery.
CG will require more home work for authentication. I doubt that it is Galand, because Galand was putting his name on the barrels, and I have never seen a Galand gun with that CG mark.
Best regards,
WC-