Remember to Observe that commencing in 2005, Rolex started engraving the serial amount on the interior bezel (also called the rehaut) beneath the crystal in the 6 o’clock posture. Potentially most significant with respect to horological history writ massive was the debut in the “Omega” caliber in 1894, a 19-ligne, https://www.watchesworld.com/a-history-of-watch-reference-numbers/