Picture of proof marks a bit dark but I see no date code
Made before 1922
1k530.3 Weight of proofed barrels, after 1924 fractions of grams no longer used.
The diamond 12 c proofmark halted in 1924.
S. Bougnet is stamped on the tubes
But Louis Bougnet was the barrel maker most noted
Biggest hint, according to the above proof chart
the Max Powder listing on the barrels was only
used between 1897-1903
Maximum service load for shotguns having undergone smokeless proof. Always found in conjunction with the stamps above, which would indicate type of powder