You should Notice that starting in 2005, Rolex started engraving the serial variety around the internal bezel (often known as the rehaut) under the crystal in the 6 o’clock place. When the crystals to the 160xx technology of Datejust watches remain made from acrylic, the sloped "pie pan" style dial https://www.watchesworld.com/a-history-of-watch-reference-numbers/