among the 209s which are already special, so we can't learn a lot from the crown-guard. The reason is, this is a proto belonging to a very senior manager in Officine Panerai that insisted on a polished crown-guard. My guess is that they took an existing one and polished it to death
. Eventually, the 209s were indeed made with polished crown-guards.
Cheers and best from the holyland,