Quick answer

The string 151.10.45.50.01.001 follows Omega's Product Identification Code format. The 45 group points to a case diameter near 45 mm. Omega's current Constellation models do not use a 45 mm case. A listing that labels this code as a Constellation has a mismatch inside the number. That mismatch does not prove the watch is fake. It does mean the code and the model name disagree, and the seller should explain why.

How Omega builds the code

Omega prints a 14-digit code in six groups. Periods separate the groups, format AAA.BB.CC.DD.EE.FFF.

  • Groups 1 and 2 (151.10): case and bracelet material plus finish.
  • Group 3 (45): case diameter in millimeters.
  • Group 4 (50): movement family and case type.
  • Group 5 (01): dial color. 01 is black.
  • Group 6 (001): version of the reference.

The same scheme runs across the catalog. A Seamaster Diver 300M with code 210.30.42.20.01.001 has a 42 mm case and a black dial. The pattern holds in most listings.

Where 151.10.45.50.01.001 breaks

Constellation cases in the current catalog run from 24 mm to 41 mm. The line started in 1952 with smaller cases. A 45 mm group does not appear in the Constellation range. Two reads are possible. The seller copied digits from a Seamaster or Planet Ocean reference and changed the model name. Or the seller invented digits to make a replica look documented. Both cases point to a listing that needs proof.

Checks that settle the question

  1. Ask for the caliber number. Constellation automatics run Master Chronometer calibers 8800, 8900, and 8901. A 45 mm diver case does not house those.
  2. Look at the caseback text. Omega engraves the PIC, the reference, and the serial. Thin laser print with no depth is a warning sign.
  3. Check the crystal. Omega etches a small Greek letter at the center. It shows under a loupe held at an angle.
  4. Ask for the Master Chronometer certificate number. Eight digits. Omega's own site confirms the number against the watch.
  5. Compare the profile. A 45 mm code implies a thick case. Constellation cases are thin, dress style, and sit close to the wrist.

What is not known

Group 151.10 does not map to a public Omega table that I can confirm. Omega does not publish a full decoder. The 45 group conflicts with the Constellation name. Serial ranges and dial variants for this exact string are unverified. Treat any listing that shows this code without a certificate number as unproven.