I agree with Daryl, this is Wm;Scott and T Baker patent 617 of 1882; "Gas vents on action face." Patent use numbers are often found on early hammerless guns by many makers. Scott,s manufactured many guns for H&H pre 1900, a business relationship that continued into the 1970,s ultimately ending with H&H,s aquisition of the Scott business.For this reason Scott patents are sometimes found on early guns attributed to H&H.

Roy Hebbes