Short answer
A fake Omega 2791 is a watch offered under Omega's vintage 2791 case reference that Omega did not build. The 2791 number sits in Omega's mid-1950s production range, so an example described as new, or one whose case and dial read as modern, is a replica, a re-case, or a parts watch. Treat the reference number as a claim to verify, not a fact. The checks below work whether the seller calls the watch a replica, a homage, an original, or a restoration.
What you need before you start
- A digital caliper for case, lug, and crown measurements
- A 10x loupe or a macro lens for dial and movement photos
- Sharp photos of a known genuine 2791 from a reference database or auction archive
- The seller's full photo set, including the caseback and the movement
- A written return window before any money changes hands
How to check a 2791 listing
- Ask the seller for a close photo of the reference number stamped inside the caseback and compare the digits to the number in the listing title.
- Measure the case diameter and lug width with calipers and match them to the documented figures for the 2791 case.
- Photograph the dial at macro range and compare the Omega logo, the signature font, and the spacing of the text to a genuine example.
- Check the movement photo for the caliber number, the finish on the bridges, and the shape of the rotor or bumper weight.
- Inspect the crown for the correct signed logo and for a profile that matches the case height.
- Compare the hand set to the dial, since mismatched hands are the most common flaw on vintage-style replicas.
- Look at the crystal and the caseback engraving under the loupe for tool marks, soft lettering, or a polished-away reference.
- Request the Extract of the Archives from the seller if the watch is sold as an original.
- Compare the asking price against recent sold results for the same reference in comparable condition.
- Ask what parts have been replaced, then decide if the watch is worth the money as a replica rather than as an original.
Red flags on 2791 listings
- A reference number that appears only in the title and never in a caseback photo
- Case dimensions that differ from the documented 2791 figures by more than a fraction of a millimeter
- Dial text printed with a modern font weight or a logo that sits off-center
- A movement with an unfinished finish, a wrong caliber stamp, or no stamp at all
- Photos taken at an angle that hides the caseback, the crown, or the lugs
- A seller who refuses a return window or who answers questions with copies of marketing text
Questions to send the seller
- What is the full caseback reference and the movement caliber number?
- Is the watch an original, a re-case, a franken, or a replica?
- Which parts have been replaced or refinished?
- Does it come with an Extract of the Archives or any service paperwork?
- What is the return window, and who pays return shipping?
Bottom line
A 2791 with a 1950s case number and a modern finish cannot be both. Pick the version you are actually buying, price it as that version, and get the return terms in writing before you pay. If the seller cannot supply a clear caseback photo and a movement photo, walk away and keep looking.