Short answer
Sellers use 398 as shorthand for the Reverso references whose caseback numbers begin with 398, including the steel Classic and Duoface models. A counterfeit of that group fails on details you can measure or feel: case width and thickness, the weight of the carriage, the tension of the swivel, the depth of the caseback engraving, and the movement visible under the sapphire back. Genuine Jaeger-LeCoultre Reverso cases are milled from solid steel, gold, or titanium and finished by hand. Copies are cast or milled from softer alloys and fitted with generic movements.
What you need before you start
- Digital calipers accurate to 0.01 mm
- A gram scale
- A 10x jeweler's loupe
- The full reference number and serial, written down from a photo of the caseback
- The official spec sheet for that exact reference
Step by step
- Write down the full reference number and the serial from the caseback photo the seller sends. Do not accept a partial number or a stock image.
- Measure the case with calipers at the widest point, then across the thickness including the crystal. Compare both figures against the official spec for that reference.
- Weigh the watch head on a gram scale. A solid steel or gold Reverso carriage carries heft that a hollowed copy does not.
- Flip the case inside the carriage. A genuine Reverso pivots on a fitted axle and settles flat in both positions with even resistance and no rattle.
- Study the caseback engraving under the loupe. Genuine engraving has crisp walls and consistent depth; laser-etched copies look shallow and grainy.
- Check the dial printing. The signature, the rail track, and the guilloché pattern should be sharp, evenly spaced, and cut rather than stamped.
- Examine the hands. Heat-blued steel shows a slight shift in tone across the surface; painted blue copies look flat and uniform.
- Inspect the movement through the display back. Look for the Jaeger-LeCoultre signature, the caliber number, and hand-finished bridges and bevels.
- Work the crown and, on a Duoface, the setting pusher. Action should be firm with defined clicks, not loose or gritty.
- Compare the strap, buckle, and spring bars. Genuine leather or alligator has fine grain and even stitching; the buckle hallmark should be sharp.
- Verify the paperwork. The warranty card, serial, box, and service records should all point to the same watch.
- Have the watch confirmed by a Jaeger-LeCoultre boutique or an independent watchmaker who services the brand before any money changes hands.
Red flags that end the inspection
- Case dimensions that fall outside the official spec by more than a fraction of a millimeter
- A carriage that wobbles, sticks, or fails to lock flat
- Shallow or uneven engraving on the caseback
- A movement with no brand signature or a visibly unfinished rotor
- A serial that does not match the reference number the seller quoted
- Missing box, card, or service history on a watch sold as complete
Papers, boxes, and service history
Jaeger-LeCoultre keeps service records tied to the serial number. A boutique or authorized service center can confirm whether a watch was sold with the reference and whether it has been serviced. Ask for that confirmation in writing. A seller who refuses, or who asks you to skip verification, has answered the question for you.
Legal and practical notes for U.S. buyers
Counterfeit watches are illegal to import, sell, or ship in the United States, and shipments are seized at the border. A counterfeit also has no valid warranty and no parts support, so a failed movement means the watch is scrap. If you want the Reverso look, buy a genuine pre-owned example with papers, or a legitimate non-branded watch with its own warranty. Paying counterfeit money for a counterfeit Reverso is the worst of both outcomes.