Got this at auction yesterday. It's missing a bell or gong. Probably a gong as I don't see a screw hole for the typical bell mount. When looking at the back view there are 3 holes not being used which I assume are for the gong. 2 holes at the top right on the movement inside the case and 1 hole at the bottom right of the door that goes right through the case (not sure why that is). Does anyone know what sort/shape of gong might be right for this clock.