Remove the stem and look in the mortise. If you see a draft hole then very likely it was drilled and just covered up with coating. If, for some odd reason, a draft hole was started, but never finished through to the bowl, just match a drill bit to the existing hole size and drill through to the bowl. If the hole is already started that will guide your bit on the proper angle. If you've used a drill before this will be a piece of cake. If you're not comfortable with tools I suppose you can return it.