A fake Omega Seamaster 300 50th Anniversary is judged by four parts: case profile, bezel insert, dial print, and movement. Replicas that get those four right pass a glance at arm's length and feel correct on the wrist. Replicas that miss them show up at once as a flat crystal, misaligned bezel markers, or dial text that is too heavy and too large. Measure the case first, inspect the dial second, and only then talk about price.

Before You Start

  • Serialized photos of the reference you are comparing against, both studio-lit and daylight shots.
  • The stated case diameter, thickness, lug width, and lug-to-lug length for that reference.
  • A 10x loupe, digital calipers, and a gram scale.
  • A neutral background and a lamp you can move, so reflections slide across the crystal and dial.

The Three Tiers You Will See

Wholesale listings almost always fall into three bands, and the band tells you what to inspect first.

  • Entry tier: mineral glass, stamped caseback, printed dial markers, generic rotor. Skip it unless the price is disposable.
  • Mid tier: sapphire crystal, correct case diameter, Miyota or Seiko-based automatic, decent bracelet. The bezel action and lume are the weak points.
  • Top tier: clone or heavily modified automatic movement, domed sapphire, applied markers, correct crown guards, solid end links with tight tolerances.

Case and Crown Checks

  1. Close the calipers across the bezel edge at three points. A copy that reads 0.5 mm over or under will sit wrong on the wrist and will not take standard straps.
  2. Measure thickness at the highest point of the crystal. Thin cases usually mean a flat crystal and a shallow caseback.
  3. Measure lug width at the inside of the lugs. Confirm it matches the reference and that the lug tips are drilled, not blind.
  4. Run a fingernail along the case flank. A genuine-grade profile has a continuous bevel and no tool chatter.
  5. Unscrew the crown fully. Check thread count, stem wobble, and whether the crown seats flush with the case tube.

Bezel, Crystal, and Insert

  1. Rotate the bezel through a full turn. It should move in even steps with no back play and no grinding.
  2. Line the triangle up with 12 o'clock. Any drift past or short of the marker is a tell.
  3. Look at the insert under a loupe. Painted numerals with ragged edges or uneven lume fill mean a cheap insert.
  4. Tilt the watch under the lamp. A domed sapphire throws a soft, wide reflection. Flat glass throws a hard edge.
  5. Check anti-reflective coating. Blue or purple tint across the whole dial is wrong; the coating on the genuine piece keeps the dial clear at most angles.

Dial, Hands, and Lume

  1. Read the dial text with the loupe. Letter height, spacing, and stroke weight should match your reference photos.
  2. Check marker alignment to the printed minute track. Applied markers should sit centered, not tilted.
  3. Inspect the hands for burrs and for uneven lume fill at the tips.
  4. Charge the lume with a lamp for 30 seconds, then compare brightness and color between the dial and the bezel pip. They should age the same way.
  5. Look at the date window if the reference has one. Framework edges should be crisp and the disc should sit close to the dial.

Caseback and Movement

  1. Check engraving depth on the caseback. Laser etching looks shallow and gray; stamped or engraved text has crisp walls.
  2. Ask for the movement name in writing. Common options are decorated Miyota 9015, Seiko NH35, or a clone automatic.
  3. Ask for a photo of the rotor and bridges. Look for Geneva stripes that stop short, sharp edges, and mismatched screw heads.
  4. Set the watch down and watch the seconds hand for stutter. A smooth sweep points to a higher beat rate.

Bracelet and Clasp

  1. Flex the bracelet. Rattling links and gaps at the end links mean loose tolerances.
  2. Check the clasp stamping with the loupe. Engraving should be deep and even.
  3. Confirm the end links sit flush against the case with no step.

What to Ask a Wholesaler

  1. Which factory or batch is this, and can I see the same unit in photos?
  2. What is the movement, and is it the version shown in the listing?
  3. What is the return window for a unit that fails a measurement check?
  4. Do you ship the watch with the bracelet sized and the caseback untouched?

Red Flags

  • Stock photos only, no unit-specific images.
  • Case dimensions given as a range rather than a number.
  • No answer on movement type.
  • Pressure claims without a stated test method.