Yes that's right. The threaded nut (never seen a nut that's not threaded, except the edible variety!) clamps the inner ring of the double angular contact bearing to the screw. The purpose of this is to eliminate axial play in the screw, though strictly speaking double row angular contact bearings have some clearance so it's not perfect.

The other end has a single standard bearing to support the end of the screw radially and allow it to expand/contract due to temperature changes.