A warranty card is not the only place a watch's serial may appear. If the card is missing, focus on identifying the physical watch and asking the seller for other reliable records.
Read the serial from the watch
Use the manufacturer's guidance or a qualified watchmaker to locate it safely. Compare the engraving with an invoice, service receipt, or other document that clearly refers to the same piece. Do not use the model reference in its place.
Run a dated status search
Enter the verified individual serial in a service that explains its sources and limitations. Keep the original result. A no-match means no matching record was found in the sources searched at that time.
Strengthen the rest of the purchase checks
Ask for proof of purchase or service, review the seller's identity and provenance, get an invoice listing the serial, and arrange independent authentication. Written return terms matter more when the paperwork set is incomplete.
If the seller will not allow serial verification, do not treat the missing card as the only issue. Pause or walk away.
Use the Physical Serial
A warranty card is optional for entering a correctly verified serial into a search.