Not a Sauer expert by any means, but it has attributes of Sauer longarms from early on such as the percussion fences and the locks are surely Sauer. But it is devoid of horn on the triggerguard bow and looks to have a pinned hinge-pin. Very interesting is the lack of a serial number. Any other Sauer type marks on the flats or tubes? Also most doubles from the 1880s had pattern welded tubes and wore either Lefaucheux, Roux or Jones underlever but a toplever was possible. I'm curious if there were older British stamps from the period on the flats? It looks to be a Model 0 or 1, and I think there were variations with changes in the model number. Is there a Doll's head extension or Greener crossbolt? Is the term "Double Grip Gewehr" on it anywhere?

Kind Regards,

Raimey
rse