Hi,
Congratulations for your recent purchase!
Calibre 23-300 was/is a very nice calibre. In fact it dates from a time when the most simple calibres from Patek Philippe had nothing to envy to the most complicated ones out of their different level of complication. That's not the case anymore. Simple calibres from PP are today very nicely finished, but the most complicated ones (manual wind chronos, tourbillon or repeater models) get a finish above their simpler counterparts.
Cheers
Dje