james-l,
Your gun should have "8936" on the barrels.
It was sold to Barratt & Son on 24 February 1890 for 23/10/0. It was marked with the Barratt & Son serial number "5234" and paired with No.5121.
It is described in part as a 28" 12-b that was choked full (left) and 1/4 (right).
Steve