re: double barrel shotgun id

i found some proof marks on this gun its showing belgium proof marks it shows proof-provisional black powder proof for breech loading huns and rifled barrels circa 1852. Also shows definitive black powder proof for breech loading guns,circa 1893.It has what i think might be the ser#66788961, 30 inch barrels,two hammers, two triggers,bead front sight, 12 guage. It also has the number 18.2 under the barrels, and on the top between the barrels it has cast steal stamped on it thank you
ken