Hi Car......welcome to TFF.
Those "small stampings of flags or coat of arms etc." are proofmarks and indicate that your shotgun was made in Europe. If one of those proof marks is an "E" with an "LG" and a crown, your gun was made in Belgium (the most likely source).....If not, I'd have to see the proof marks to tell you where it was made.
Since your shotgun is a muzzle loader, it was probably made before 1870 or so. This is a blackpowder gun and should never be used
with modern smokeless powder.
W.A. Moody & Co. is most likely the store or chain of stores that imported the gun and put their name on it.