SIT,
The reinforced frame seems to be typical of the F. or Fs. Dumoulin guns. Referring again the Guns Intl. site you will see significant differences in the level of finishes on the four or five guns listed. The guns advertised by doublegunhq and boisegun have both been on the site for quite sometime as has the 16ga. sideplated gun at Cabelas. The 16ga. is the twin to my gun with minor variation in the engraving and the carving of the fences. The doublegunhq's ad seems to be close to the condition of the gun you have but your gun shows slightly more engraving. I would think that about $750. would be right.
Note that most of these guns are light for guage. My 16 is 5lbs. 8ozs. For those conjecturing about date codes, my gun is marked '43. I fully admit to Drew's hesitation in interpreting said codes.
