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

https://griffinucyk847.iamarrows.com/is-it-worth-driving-from-chula-vista-to-la-jolla-to-sell-a-rolex

If you’re checking a Rolex in San Diego, the reference number is engraved between the lugs at 12 o’clock, under the bracelet. Don’t pry it off just to look. Have a watchmaker or reputable buyer inspect it before you sell or borrow against it.