French? Smoothbore Double-barrel Conversion Musket

[MarcCanada]

Hi all,

I just picked up this mysterious, possibly French smoothbore double-barrel shotgun at an Antique show in Montreal for 280 CAD. The seller couldn't identify it, and I'm equally stumped so far.

I found this similar piece on a French auction site: https://www.gazette-drouot.com/lots/15852170-fusil-de-chasse-a-percussion---
Also similar: https://www.gunsinternational.com/g...-end-gorgeous-st-etienne.cfm?gun_id=102631119

Does any know what I might have here?

Here's what I know:
-Lock plates are bear the name "Jean 'd'Courcy"
-The underside of the barrel (right near the breech) is covered in various undecipherable markings, but I I can make out "Ruban Fer" (Iron band), and the "CF"
-The side of the barrel bears "20" and a crown?
-The underside of the stock is carved into a bearded man

Thanks so much!

 

[Story]

-The side of the barrel bears "20" and a crown? <- this would imply that it's a 20 bore. Measure the muzzles?