Belgian antique AD. Bouquin. Liege???

Hi all, I'm new here.
I checked at the blue book site but couldn't find anything there. I picked this shotgun up as an antique, but can't find any information on it. It appears to have Blegian proof marks as listed in the WW Greeners gun and it's developement. Could anyone help me with more specifics, like date of manufacture, manufacturer, proof pressure??

Thanks
The flats of the barrel have:
a script EL
another intertwined script something, G upsidedown L with a couple of bumps??
3 diamonds in one on a stick
1Kg 418
u
M with a . on top
Lion over a line over a P.V
crown ontop of oval with ELG* inside
12-70 in a sideways horseshoe, Ohmega?
the other side has a almost Y !!
choke 18.3

The action has siome similar marks with the lion?PV and the diamond thing and the Y?11 with a 1 seperate
sn 490x

The rib says:
Siemens-Martin-Steel
AD. Bouquin.Liege

The gun is engraved, not high quality though, extractors, barrel length 28 1/4" with single bead. Chopper lumps with greener cross bolt, nice blueing, finish about 95%

The gun is light, points quick, feels great. solid butt plate.

Any thoughts?
TIA
lar.