Eric, the only markings that have any meaning are the model number, the serial number on the bottom of the grip and any letter "N" that may appear on the left side of the grip frame (the other side, not the one in your photo) and on the back of the cylinder. It's natural to assume there is some meaning to the others, but that would be incorrect, unless you're a S&W employee matching up parts at the factory.
You indicate you have a letter of authenticity. Is it from Mr. Jinks at S&W? What did he say about finish, etc.?