Quick answer

A fake Rolex 178273 is a copy of the Datejust 31 in Rolesor, the mix of Oystersteel and 18 ct yellow gold that Rolex uses for two-tone models. The genuine reference has a 31 mm case and calibre 2235. Copies sell for $150 to $600. Genuine examples list for about $7,000 to $13,000 on the secondhand market, so price identifies most of them.

Reference 178273 at a glance

  • Model: Rolex Datejust 31, mid-size
  • Case: 31 mm, Oystersteel and 18 ct yellow gold
  • Movement: calibre 2235, automatic, 28,800 vph, 48-hour power reserve
  • Crystal: sapphire, Cyclops lens at 2.5x over the date
  • Bezel: fluted, domed, or diamond set, depending on the dial variant
  • Bracelet: Jubilee or Oyster, with gold center links on the Jubilee
  • Water resistance: 100 m
  • Production: about 2004 to 2018, then replaced by the 278273 and calibre 2236

What copies get right

Case size, dial layout, date at 3 o'clock, and crown at 3 o'clock match on most copies. Stamped fluted bezels read as gold from two feet away. Two-tone Jubilee bracelets copy the link shape. At 800 pixels wide, product photos hide most of it.

What copies miss

  • Gold content. The genuine bezel and center links are solid 18 ct gold. Copies use gold plating of 2 to 5 microns or gold-tone PVD. Plating thins at the clasp, the crown, and the link edges.
  • Weight. A two-tone Datejust 31 with a Jubilee bracelet sits near 100 grams. Copies land 15 to 25 grams lighter because the case and links are steel under the plating. This is the fastest test with the watch in hand.
  • Date and Cyclops. The genuine lens magnifies 2.5x. Copies show 1.5x to 2x, and the date wheel sits off center.
  • Movement. Calibre 2235 runs at 28,800 vph with a 48-hour reserve. Many copies run a Seagull ST16, an ETA 2824 clone, or a Miyota at 21,600 vph. A timegrapher shows the rate and the beat error in seconds per day.
  • Print and engraving. Dial text on the genuine part is thin and sharp. Copy fonts sit heavier. Rehaut engraving on copies is shallow and misaligned with the minute track.
  • Service. No copy has a parts network. A repair bill can pass the price of the watch.

Seller terms have no standard meaning

"First copy", "1:1", "AAA", and "mirror quality" carry no fixed definition across sellers. Request three data points before payment: the movement name and maker, the case and bracelet metal, and the plating thickness in microns. A seller who cannot name those three is reselling stock from another party.

Photos to ask for

  1. Macro of the rehaut and the date window, with the crown at 3.
  2. Clasp stamp and coronet, plus the bracelet end links.
  3. Caseback and the reference stamp between the lugs.
  4. Timegrapher screen: rate, amplitude, beat error.
  5. A lume shot in a dark room.

Legal status in the US

Counterfeit watches are illegal to import, ship, or sell in the United States. 18 U.S.C. 2320 covers trafficking in counterfeit goods, and the Lanham Act covers trademark claims. CBP seizes counterfeit shipments at the border. Personal possession carries less risk than resale, but resale and import carry criminal exposure.

Bottom line

Reference 178273 is a 31 mm two-tone Datejust with calibre 2235. A copy can match the shape, the dial, and the bracelet pattern. It cannot match solid gold, 100-gram weight, or a Swiss movement with a parts network. Read the movement spec and the metal spec before you compare prices.