Her are a few more photos. They appear to have cylindrical tips, like maybe they were inserted into something and served as a sort of axle? I wonder if these "pegs" were inserted in to something and as the tool pivoted, the angled stub caused the work to bend around? The third photo is of another pair from the same place that are similar, but have the angled "shelf" reversed on the other side. The museum also had a half dozen vintage fireplace tongs with the blacksmith stuff. I suggested they put those with the household fireplace stuff!
Phil.