Each of the 12 pieces has a different numeral painted in red instead of black. And, as the 3 is hidden by the seconds subdial, the piece which should have a red 3 has, instead, all numerals in red.
Other specificity: the minute markers between the 7 and the 6 are spelling “P I S A” (this detail can hardly be seen on the low quality photos of the “6” piece and is completely invisible on the image of the “12” piece).
I’ve had to dig quite a lot to find these images. While posting the tread this morning, I had given up searching but finally tried again…
credit: pisa1940.com
credit: flawless crowns
credit: chronomania
credit: flawless crowns