Hello,Hoarder. Is that a true radius on the bottom of the plane, or, on the blade? Most plane makers made matched sets of hollows and rounds. I believe the plane would be named after the profile it cut, as opposed to its shape.So, if yours is a true radius, I believe yours would be a hollow. My other thought is that yours may be the mating plane used to cut the profile on a bullnose plane. Profiles cut into wooden planes needed the mating plane to cut that profile. Make sense? Corrections,please, if I have explained this incorrectly. Regards, Lou