Rolex serials are a lookup table, not a code: numeric serials before 1987, letter prefixes from 1987 to 2010, and deliberately random serials after that. All published tables are approximate — letters ran concurrently and production overlapped — so this tool answers in year bands and says so. Pre-2005 the serial is engraved between the lugs at 6 o'clock; later watches carry it on the rehaut.
A band, honestly: even Rolex's letter prefixes ran concurrently, and every published table is an estimate. The serial dates the case's production era, not the dial or bracelet on it today, and post-2010 random serials date nothing at all by design — for those, the warranty card is the record. A serial whose era disagrees with the reference is itself a finding.