Looks like it, too.... Just kidding!
Ok, smokeless proof, looks like a decent boxlock gun, probably post WW1.
Well used, have it checked, but if OK, heavy loads not a good idea.
1kg4(?) was the weight of the barrel set at proofing (1.4 kg).
The crown over D may be Doumoulin (spelling?).
One of the marks on the barrel set (funny h) is the year date code, looks sorta 1929.
The C (Omega sideways) with 12-70 is after 1924.
That's it, you are on your own potty from here!
Have fun.