Be sure to Notice that starting in 2005, Rolex began engraving the serial number to the inner bezel (often known as the rehaut) beneath the crystal with the 6 o’clock place. Although the crystals around the 160xx technology of Datejust watches remain produced from acrylic, the sloped "pie pan" type https://www.watchesworld.com/a-history-of-watch-reference-numbers/