I carry a 3rd gen bought back in November I have to disagree with the serial# including a Z here is a pic of mine SN visible.
They need to update the Pics on their website as it is still showing 2nd gen as new guns.
3rd Gen:
It has Heine8 dovetail sights
Millennium on one side and PT 145 Pro on the other
Rail
Front of the trigger guard is smooth
SA\DA
Earlier:
1: the barrel showing at the ejection port is black
2: no rail
3: the word PRO is not there
4: the sights are not dovetailed
5: the front of the trigger guard is stippled.
6: the profile of the sights is different