A couple simple modifications made. I figured I'd share them and save someone a little bit of time. The pin has the appropriate sized hole already in it. I've added a hole to the base and a bowling ball with peg that should fit in the hole.
Depending on your printers tolerances you may want to scale the bowling ball down 1 or 2% for proper clearance.
The author remixed this model.
I added a bowling ball embellishment and modified the pin to have the necessary hole in the bottom.