Please Take note that commencing in 2005, Rolex commenced engraving the serial number to the inner bezel (often known as the rehaut) underneath the crystal on the six o’clock placement. When unsure, Select a Serpenti in two-tone metals—a modern, putting watch that could hug your wrist like a 2nd skin. https://www.watchesworld.com/a-history-of-watch-reference-numbers/