If this is circa 1888 it should be a Fifth Variation "type b" (1882-1917) with a dolls head extension on the top rib. Even though Titanic Steel barrels were introduced in the 1890's, these damascus hammer doubles were popular right up to WWI. The curved "fish tail" top lever is very "cool" and has appeared on high grade hammerless models too. It's thought that the design was to provide clearance between the lever and the right hammer when opening. Not seen on any other doubles (American, English or European) of any era to my knowledge. I think the asking price is reasonable...I'd buy it if I were you.
