According to Malcolm, the family used as a paperweight.
More to the point, based on the research that Angela Bowey and I did in preparation for the Vasart article in the PCA Bulletin, it seems likely that all paperweights they received from Pirelli already had a hole drilled in them and maybe also included the threaded fixture. It would be just like the Lassman's to create a base for the paperweight if they wanted to keep a few for display or even sell a few this way.