If it has a patent date of Oct. 4, 1887, that is the A.C. McFarland Patent No. 370,966 for his trigger-plate hammer gun. It was built by the Syracuse Forging & Gun Co. in Syracuse, New York, and then after the 1889 fire in the Syracuse factory and move to Batavia by the Baker Gun & Forging Co. in Batavia, New York.
Everything you could want to know about those doubles is in The Double Gun Journal, Volume Nine, Issue 2, pages 63 to 77.