They are almost always colour-matched to the trim and are among the most commonly missing pieces on a used vehicle.
A cap is replaced because it has fallen off, because a technician broke the retaining tab during a repair, or because the plastic has discoloured. Losing one is not a functional problem, but an exposed bolt head or hinge in the middle of a seat back is immediately noticeable, and the replacement is inexpensive.
Match the cap by position and by shape. A cover for a seat belt anchor has a different aperture from one for a recliner hinge, and the left and right sides differ on most seats. Colour from the trim code. Where the cap clips into a specific housing, check that the housing is intact, because a broken housing will not hold a new cap.
