Answer first

"4th generation" is not an Omega term. No Omega catalog, service record, or press release uses it. The label comes from replica sellers and forum threads. It means the fourth version a factory or seller has released of a watch that copies the 1957 Speedmaster. There is no shared standard. A 4th generation from one seller can differ from a 4th generation from another seller. Two watches can carry the same number and different dials.

Which 1957 Speedmaster sits behind the keyword

Three references get called "1957."

  • CK2915. The first Speedmaster. Released 1957. Steel case at 39 mm, broad arrow hands, tachymeter scale on the bezel, no crown guards, caliber 321.
  • Reference 3594.50.00. A 1997 re-edition. Case measures 42 mm.
  • Reference 311.10.39.30.01.001. The 2017 Trilogy Speedmaster 1957. Case 38.6 mm, caliber 1861, broad arrow hands, run of 3,557 pieces.

Sellers apply generation numbers to all three. Ask which reference the replica copies before comparing photos.

What changes between replica generations

Factories do not publish change logs. Buyers build the list from side-by-side photos. Points that move between versions:

  • Dial print. Font weight of "OMEGA," letter spacing, and the position of the word "Speedmaster" above the center.
  • Lume. Color and texture. Older versions run green or orange. Later versions sit closer to the pale cream used on the 2017 watch.
  • Bezel insert. Numeral font, spacing, and the shape of the dot at 90.
  • Hands. Broad arrow width at the base, and the length of the chronograph seconds hand.
  • Crystal. Dome height and edge profile. Sapphire on some versions, mineral glass on others.
  • Movement. The ST19 hand-wound chronograph appears in most versions. Quartz appears in low-cost ones. Case thickness follows the movement.
  • Caseback. Engraving depth, text, and the seahorse or hippocampus stamp.

How buyers check a 4th generation claim

  1. Ask for a dial photo at macro range with the hands at 10:10.
  2. Ask for a bezel photo at 12 and at 90.
  3. Ask for the case flank and the crown side.
  4. Measure case thickness with calipers. Compare to the reference the seller names.
  5. Charge the lume with a phone light for 30 seconds. Photograph after 5 minutes.
  6. Compare the movement photo to the ST19 layout: two sub-registers, column wheel visible under the bridge.

What cannot be confirmed

Factories do not keep public version histories. Forum posts are the main record, and they mix sellers, dates, and factories. A specific date for a 4th generation release, or a full parts list, cannot be verified from an official source. Treat any fixed date as unconfirmed.

Legal and value notes

A replica is not an Omega. It has no Omega warranty, no Omega service, and no resale value through Omega channels. In the US, selling counterfeit goods falls under 15 U.S.C. § 1114, and import of counterfeit goods is barred by 19 U.S.C. § 1526. Customs officers can seize a shipment.