Remember to note that commencing in 2005, Rolex commenced engraving the serial variety over the inner bezel (generally known as the rehaut) beneath the crystal in the 6 o’clock situation. ” Such as, in case you opened a Rolex catalog while in the mid-’60s, you might’ve uncovered the next references https://www.watchesworld.com/a-history-of-watch-reference-numbers/