This little one appears to be new-old-stock. We have acquired a goodly number of these, and they are in new-like condition. The small 1/2-inch knob has the inset back screw.
This is the type of knob that was used on small drawers like the ones in roll-top desks, or on the lift-up windows on the old lawyer’s bookcases. The knob projects 3/8 inch from the surface.