A GMT-Master II's bezel and reference can help identify its configuration, but neither is a unique theft identifier. To check whether a particular watch has a report, use its serial number and confirm that number on the piece itself.
Ask for the serial before the transaction
Request a legible image of the actual watch and compare it with the card, invoice, or service documents. If the seller shares only the reference, explain that the reference applies to a model family and won't identify this GMT-Master II in a database.
Make the result belong to the watch
Search the verified serial and save the result date. At handover, compare the engraving again. If the number is hidden under the bracelet, ask a watchmaker to inspect it safely; a pre-sale search on an unverified photo may refer to another watch.
What a match or no-match tells you
A match needs careful comparison with the report and follow-up with the service. No match means no record was found in the searched data at that moment. Neither result establishes authenticity, seller title, or a complete ownership chain.
Check the Individual Watch
Use the GMT-Master II serial and retain the result with the purchase documents.