If you’re checking a Rolex before selling or borrowing in San Diego, the...
https://wiki-stock.win/index.php/How_Do_I_Check_If_My_Rolex_Is_Original_Before_I_Sell%3F
If you’re checking a Rolex before selling or borrowing in San Diego, the reference number is engraved between the lugs, under the bracelet. Don’t force it off. Have a watchmaker inspect the watch, and get any loan terms in writing before handing it over.