Well, considering that the only 28 gauge Model 23s made were made as part of a four gun set,and unless they were some special order, it must have one of them. They were the Golden Quails and the Classics, 500 of each gauge in each set. The Quails were straight grip with silver nitrate finish on the frame. The Classics were pistol grip with blued frame and gold inlays.
This must be a set of the Classic. The frame is blued, they are pistol grips and beavertail forends. I know the 28 and the 410 are on the small frame.