Hi Montenegrin..not sure that you hammer gun is Sauer made. The reason I state that is in your post you note that there is not a Dolls head or Greener cross bolt (general Sauer attributes) plus no other Sauer markings. No serial number is very odd unless it was produced in the 1855-1870 time period. Also, the barrels appear to be fluid steel which if the piece does date to 1855-1870 would be unheard of as Sauer shotguns produced in that time period would have been outfitted with Damascus barrels. The fences (to my eye anyway) appear to be much taller and shaped differently than Sauer fences for their early hammer guns. Do your barrels carry the Sauer man with staff trademark on the barrel flats? A bit more information (if available) might help determine whether or not your shotgun was Sauer made. Thanks, Jeff S.
