Rolex engraves a unique, 5 to 8 digit serial number to every watch it makes that helps determine the approximate date, or year of production for that particular watch. These sets of numbers, for example 28000 for the year 1926 or Z000001 for year 2006, are inscribed by machine on the side of the watch case between the lugs at 6 o’clock. In 2005, however, Rolex began engraving the serial numbers onto the inner rim of the watch, called the “rehaut”, for stylistic reasons. Beginning in 2010, Rolex stopped following any sequential numbering system or order altogether and now engraves its watches with a randomized, arbitrary unique identifying number. While it had been relatively easy to ascertain a watch’s approximate age, or year of production using a database of lists assembled over the years, this will no longer be possible with these new random mixed serial numbers (typical samples include “MN72LK22” or “ JH675TR1” ).
While there is no “Official” Rolex Serial numbers database list from the Rolex Factory that shows dates of production, this chart below lists all the serial numbers gathered by proven authorities over the years. See the list below by production year