The short answer
A counterfeit b3484 is a watch offered with the B3484 marking that fails the checks a genuine example passes. The code on its own settles nothing. Plenty of real watches have stamps that look odd after a service, and plenty of fakes have stamps that look perfect in a phone photo. What separates them is whether the engraving, the movement, the paperwork and the seller's story hold together when you push on each one.
I treat any listing that leans hard on a four or five character code as a prompt to slow down. Codes are easy to copy. Fit and finish are not.
What the B3484 marking is and is not
Buyers search this string because it turns up on casebacks, hang tags, warranty cards and auction lot sheets. It reads like a reference or a batch number, and sellers often present it that way. But a string on a caseback has no authority by itself. Reference numbers identify a model family. Serial numbers identify an individual watch. Batch and lot codes belong to production paperwork, not to the case.
So the first question is not "is B3484 real." It is "which of those three things is this seller claiming it is, and does the rest of the watch agree." When a seller can't answer that cleanly, you have your answer.
The checks that decide most cases
- Engraving quality. Factory engraving is cut or laser-etched to a consistent depth with crisp interior edges. Fakes show rounded shoulders, uneven depth, and fill from polishing leftover from a stamped blank.
- Number logic. Reference and serial numbers follow patterns that change by era. A number that fits a 1990s case paired with a dial from a much later run is a mismatch, not a rarity.
- Movement. Look at the balance, the finishing on bridges, and the shock protection. Clone movements photograph well and feel wrong in the hand: gritty winding, a rotor that rings, sharp bevels.
- Case and bracelet fit. End links should sit flush with the lugs with no gap and no rattle. Genuine tolerances are tight enough that you feel the difference before you see it.
- Papers matched to the watch. Card, booklet, and tag should agree with the case numbers. Reprints have flat ink, wrong fonts, and no wear pattern that matches the age of the watch.
Listing red flags
Stock photos on a used watch. A price far under market with a story about a quick sale. Refusal to send a movement photo or a macro shot of the caseback engraving. Pressure to move the deal to a messaging app. Any one of these is a reason to walk. Two of them together is a pattern.
Ask for a video with the watch running, the crown operated, and a coin or card next to the case for scale. Fakes are built to survive a still photo, not a continuous minute of handling.
Verification that actually counts
Manufacturer websites list model references and specifications, but no brand will certify a specific watch from photos. Rolex routes owners to authorized service centers for that call, and the same applies across the industry. A service estimate is worth more than any forum opinion.
On the legal side, US Customs and Border Protection treats counterfeit watches as prohibited merchandise and seizes them, and trafficking in counterfeit goods is a federal crime in the United States. Swiss authorities take the same view of goods moving through their territory. If a deal depends on skirting that, it is not a good deal.
If you already bought one
Stop wearing it, photograph everything including the packaging and the conversation, and get a written opinion from a watchmaker who handles the brand. Chargeback windows are short. Open the dispute while you still have options, not after.