If you’re checking a Rolex in San Diego, the reference number is engraved...

https://www.sandiegouniontribune.com/2026/10/06/6-things-san-diego-rolex-owners-should-know-before-they-sell/

If you’re checking a Rolex in San Diego, the reference number is engraved between the lugs at 12 o’clock, under the bracelet. Have a watchmaker remove it rather than using a knife, and don’t post clear photos of the serial number.