We have had several small low domed Arculus weights, and we have 12 shot glasses in our collection. All the shot glasses are well under 2 inch diameter, whereas the paperweights have been more than 2 inches diameter. So I don't think the one that started this thread was ever a shot glass.
There are lots of other Arculus / Walsh Walsh millefiori paperweight items, such as jugs, bowls, wine glasses and tumblers, of which we own examples, and I have heard of - but not seen - a tea cup and saucer. None of those had enough glass over the canes to make a good paperweight if damaged.