They look like cleco pliers for sheet metal, aircraft work. They open the cleco's to inset in holes to keep the sheet metal in place for riveting. Look on ebay for cleco and you will see many that look very similar to those.
Nose ring pliers that I've seen of that age usually have a threaded post as an adjustable positive stop, similar to glass & tile pliers. Also, they don't have that cleft in the one jaw.
Still, the curve of the jaws does look like it compresses something.
Yes, Hog Ring Pliers, US Patent: 213,618