Make sure you note that commencing in 2005, Rolex began engraving the serial amount around the interior bezel (generally known as the rehaut) beneath the crystal in the six o’clock place. Although the crystals around the 160xx technology of Datejust watches are still created from acrylic, the sloped "pie pan" https://www.watchesworld.com/a-history-of-watch-reference-numbers/