Paul, will you hunt it? I shoot a A5 Magnum, as my duck gun. It is a Japan made gun, so I shoot 3" mag steel in it. I have screw-in chokes. I tried to hunt it with wood stock, but that was futile. I first broke a forend, then a new butt stock. Bought a plastic stock for it and have shot this gun for over 25 years. Keep it well oiled, clean it only when I get it in the salt or really mucked up... and it serves me very well. I think I paid around $350 but it had a slug barrel on it, so I spent another $200 I think or close on the Browning barrel for ducks. I got a 26", wish I had the 28" on it. I keep my eyes open all the time for another, just to have one in the safe, but honestly, unless I loose this or it gets stolen, I won't need another.
A year ago, I finally had to replace a part. The magazine keeper wore out. It is a folded over piece with pivot pin holes in it. One of the holes broke through to the edge, and the keeper could teter out of alignment. $18 from Brownell's and good for another 25 years!
If you get a Belgium gun, it will be fixed choke or poly choked. To install a newer barrel, I think the fore stock needs to be worked or replaced. As the Belgium barrels/lugs were narrower is what I understand. I don't have first hand knowledge.
I would like a Light 12 for trap... and a Sweet Sixteen for upland! I keep my eyes open, but so far just the Magnum in my safe.