Short answer

"Reverso 398" is not a complete Jaeger-LeCoultre reference. JLC reference strings run to nine characters, in the form Q3988482. The leading digits point to a model family, and the remaining digits carry case metal and dial variant. A seller who quotes "398" alone has given you a partial number. Ask for the full string, photos of the caseback engraving, and photos of the guarantee card before you judge the watch.

Public data on this specific fake is thin. Treat any single "tell" as a hint, not proof.

What the Reverso is

JLC launched the Reverso in 1931. The case slides in a track and flips 180 degrees so the solid metal back faces out. Monoface models show one dial. Duoface models carry a second dial and a second time zone on the reverse. Most Reverso references have no display caseback, because the back is a working surface.

Case and swivel

  • Machining the track and carriage is the costly part of the case. Most fakes fail here.
  • A genuine case flips with a firm spring detent at 180 degrees and stops flat. Fakes wobble, over-travel, or sit loose in the track.
  • Check the gap between the carriage and the outer case on all four sides. An uneven gap shows on the wrist.
  • Fakes often run 1 mm to 2 mm thicker than the reference. Compare the measured thickness against the figure published on the JLC model page.
  • Steel Reverso Classic and Tribute cases sit near 45.6 mm by 27.4 mm, with size changes by reference. Measure the actual watch.

Dial, hands, crown

  • Print the reference page. Compare logo weight, font, and spacing at 5x magnification.
  • Heat-blued hands show a deep even blue. Painted hands look flat and purple under a light.
  • Applied markers sit proud with sharp bevels. Glued markers show a glue line.
  • Count the crown flutes and compare the shape. Some references carry a cabochon; a plain crown on those references is wrong.
  • Guilloché texture should be cut, not stamped. Stamped texture looks soft under raking light.

Movement

Calibre 822 drives many Monoface references. It is a manual-wind movement with 108 parts, a 45-hour power reserve, and 21,600 vibrations per hour. You will not see it through the back on most references. A seller showing an exhibition caseback on a reference that should have a solid back has shown you a fake. The Duoface uses a different calibre with a second time zone module. Ask for the calibre number and check it against the reference.

Price and paperwork

  1. New steel Reverso models start above USD 7,000 at retail. Current prices change; confirm with an authorized retailer.
  2. Fakes sell for USD 200 to USD 700. A "Reverso" offered at USD 1,200 with box and papers is not a bargain.
  3. Match the serial on the caseback to the guarantee card and to any service record. Mismatched numbers are common on fakes.
  4. Ask for a photo of the caseback engraving under raking light. Laser etching looks shallow and grey next to deep engraving.
  5. Ask for the strap and buckle. Stamped buckles with soft edges appear on fakes.

What to do next

Take the full reference, the caseback serial, and the watch to a watchmaker who services JLC. A bench check of the swivel, the case dimensions, and the movement takes minutes and settles the question. Confirm the reference on the official JLC site first, since a wrong number means the rest of the comparison is wasted.