I have certainly seen lead hem weights, but with two holes, like large buttons, to sew through. And I agree, why the serrations? Do they both have only one hole? If two, I would have thought them to be childs 'whizzers', the musical toy that was spun on string and made a noise. With only one hole, they must have been nailed to something, or maybe spun like a top with a nail. Bit of a puzzle, quite honestly.
Jerry