Brunswick Dura-King Duckpin Bowling Pin

This is a used Brunswick Dura-King bowling pin. I usually collect unused or new old stock pins only but quality duckpins are hard to find. Aside from the evidence of moderate usage (scuffs on the plastic skin from the pinsetting equpiment) and dents (from ball impacts compacting the wood underneath the plastic skin, the pin is in fine condition. The medallion is bright and complete. Also notable in this and the Brunswick King in my collection is the presence of machine-punched holes on the medallion label. There are several sets, maybe a dozen or 15 on a label and arranged in a grid like pattern that is suggestive of Braille. Curious as you can't feel the punched holes, only see them. Does anyone know what these punch holes mean? In any case, another cute, plump little pin with a bunch of character.