Short answer
A "fake Jaeger-LeCoultre 1398420" is a counterfeit of a Reverso Classic model. Jaeger-LeCoultre reference numbers carry a Q prefix, so the full form is Q1398420. A listing that shows the bare number, no box, no papers and no service record is a common front for a counterfeit. The number alone proves nothing. Confirm the reference with Jaeger-LeCoultre before you send money.
I could not verify the exact case size, movement and dial variant tied to 1398420 from public sources. Jaeger-LeCoultre publishes current references on its own site. Ask the brand or an authorized dealer for the spec sheet for that number, then compare.
What the number means
Jaeger-LeCoultre builds the Reverso line around a case that slides on a carriage and flips to show a solid back. The line started in 1931. Reference numbers sort by family, case size and dial. The 139 group sits in the Reverso Classic range. Numbers in that group span more than one size and more than one dial, so a seller who quotes "1398420" without a photo of the case back is hiding the part that matters.
Checks that separate real from fake
1. Case back engraving
Genuine Reverso backs are engraved with the reference, the serial and the case metal. Lines are crisp and even. Fake engraving looks shallow, wobbly or laser-etched. On a Reverso the back is the display surface, so this is the first place to look.
2. The flip mechanism
The case should slide up on its rails with light pressure and no rattle. It should click into place at both ends. A fake often grinds, sticks or wobbles on the carriage. Test it five times in each direction.
3. Dial printing
Look at the words Jaeger-LeCoultre and Reverso. Letters should be sharp under a loupe at 10x. Fakes show thick strokes, uneven spacing and bleeding at the edges of the printed text.
4. Movement and finishing
Genuine JLC movements show Geneva stripes, polished screws and beveled bridges. Fakes use stock movements with no finishing, or printed plates. Ask for a clear macro photo of the movement through the case back, or a photo of the display back if the model has one.
5. Papers and price
A Reverso Classic sells in the four figures on the secondary market. A price under $700 for a steel model is a signal, not a bargain. Ask for the warranty card, the dated invoice and the serial. Call the brand and check the serial against the reference.
If the watch is already in your hands
- Stop wearing it. Do not open the case.
- Photograph the case back, dial and movement.
- File a dispute with the payment provider inside the window.
- Report the seller to the National IPR Coordination Center.
- If the watch crossed a border, contact US Customs and Border Protection.
What is unknown
Public data does not confirm the exact build of Q1398420. Treat any listing that quotes detailed specs with no source as unverified. The brand, an authorized dealer or a watchmaker with JLC parts access are the only reliable checks.