Hi, I'm really new to this board and have tried to search for the answer to my question, but have had no luck. I currently own a PT-145 and wondering how to tell the difference between if it is a 3rd gen or not? Is there a way to tell by the serial number or the type sights? The right side of firearm has PT145Pro Cal .45ACP and the other has Millennium. Thanks for helping me with this in advance.