Yes a very nice high quality double!

Monobloc has the letter h which is 1929.
Barrels have underlined letter W or w.
W is 1999.
w is 1984.

I think it looks more like a capitol W 1999, but not certain.

The monobloc appears to have a shotgun proof mark which is the elongated omega shape with what looks like maybe a 20 or 28 stamped inside.

Sorry but no idea who the action or barrel maker might have been.

It is certainly a beautiful and very usefull rifle.
Thankyou for showing us!