Short Answer

The 126719BLSO is the 18k white gold branch of the GMT-Master II family: a 40 mm Oyster case, a bidirectional Cerachrom bezel with a two color ceramic insert, an Oyster bracelet, and caliber 3285 with a 70 hour power reserve. On the GMT-Master II line, the meteorite dial is reserved for the white gold references. A replica can copy the silhouette, but it rarely copies the metal, the ceramic insert, the stone dial, and the hand stack all at once. Judge a build on those four points before you judge anything else.

Prerequisites

  • A 10x loupe or a phone macro lens
  • A digital scale accurate to 0.1 g
  • Digital calipers reading to 0.01 mm
  • Daylight or a 5000K lamp for color checks
  • Access to a watchmaker if you plan to open the case back

Inspection Steps

  1. Weigh the watch with the full bracelet attached. Gold is close to twice as dense as steel, so a white gold GMT on a complete Oyster bracelet lands near 200 g or higher. A plated steel copy sits around 150 to 165 g. A tungsten build gets closer to the right number, but the head often feels heavier than the bracelet, which is the wrong distribution.
  2. Measure the case with calipers. Check 40 mm across the bezel and roughly 12 mm through the case, and confirm a 20 mm lug width. Replica cases often run 0.5 to 1 mm thick, and the lug curve sits flatter than the original.
  3. Examine the bezel insert under the loupe. Genuine Cerachrom is one molded ceramic piece with the numerals filled by a thin metal layer. Replica inserts use paint, a decal, or a light metallic sputter. Look at the seam where the two insert colors meet at 6 and 18 o'clock. The original line is razor sharp. Copies show bleed, jagged edges, or a color shift under direct light.
  4. Study the dial. A genuine meteorite dial is a sliced and etched piece of Gibeon meteorite, so the Widmanstatten pattern is one of a kind and shifts as you tilt the watch. Fakes print the pattern on flat stock or seal a thin slice under resin. Look for a repeated pattern that appears more than once on the same dial, and for a flat, even sheen instead of banded metal luster.
  5. Test the GMT hand. Pull the crown to the second position and turn it. On a correct build the hour hand jumps in one hour steps while the 24 hour hand stays put. On a cheap build the 24 hour hand jumps instead. That single behavior is the fastest tell on the whole watch.
  6. Check the crown action and the date. The crown should engage with four clean positions and no grit. The date should flip inside a few minutes of midnight, not at 11 p.m. or 1 a.m.
  7. Rock the bracelet and work the clasp. Solid links should not rattle. The Oysterlock should close with a firm click and the safety latch should sit flush. Cheap builds use hollow mid links, stiff hinges, and stamped clasp codes that do not match the case reference.
  8. Inspect the case back and the lugs only if you can do it without damage. Genuine engraving is crisp and shallow, cut by a laser, with the reference and serial between the lugs. Replica engraving is often deeper, wider, or absent on the inner case back.
  9. Open the case back with a watchmaker present. Note the movement family. A clone 3285 or a converted ETA 2836 is common. A DG3804 is the budget option. Check the beat rate at 28,800 vibrations per hour and the power reserve near 70 hours on a wound clone.

Movement Tiers to Expect

Three tiers show up in the market. The entry tier uses a DG3804 with a low grade finish and a rough hand stack. The mid tier uses a converted ETA 2836, which keeps good time but adds thickness and shows the wrong hand behavior in some builds. The top tier uses a clone 3285 with a proper jumping hour hand. Ask which one is inside before you compare two watches on price alone.

Red Flags

  • Weight listed as "gold plated" but quoted near genuine gold figures
  • Bezel colors that shift toward purple or orange in daylight
  • A dial pattern that repeats in the same spot on every photo
  • A 24 hour hand that moves when the hour hand should
  • Clasp code that does not match the reference between the lugs

Legal Note for US Buyers

Counterfeit watches are illegal to import and to sell in the United States. Trafficking in counterfeit goods carries criminal penalties under federal law, and US Customs and Border Protection seizes shipments at the border. Owning a replica is not the same as trading one, but buying a replica to resell as genuine is fraud. Treat this guide as an identification resource, not a buying endorsement.