There is a story line to these "Pistol Grips" as they were titled by the Patent holder. However, they were clearly listed as a benefit to "fighting" or for fighting to provide a solid grip. I believe only 5,000 were made and if you notice in the Patent drawing? It was originally designed for the Harrington and Richardson. They have matching numbers with the gun. I have only one in my collection and it's also on an Iver Johnson hammerless .32 and it's in poor condition but it's matching. The patent is dated May 10,1904 so guns having this feature are considered Curios.
Murph