A fake Audemars Piguet ref 14791 rarely announces itself. It looks like a 36 mm Royal Oak, and that is the whole problem. The tells sit inside the case and in the paperwork, not on the front of the dial.
So here is the short answer I give people: get two things before you negotiate. An Extract from the Archives from Audemars Piguet, and a watchmaker who will open the caseback while you stand there. If a seller pushes back on either request, you have your answer already.
What the 14791 actually is
The 14791 belongs to the 36 mm Royal Oak family that sits beside the better known 14790. Octagonal bezel, eight hexagonal screws, integrated bracelet, a thin automatic movement, no cyclops over the date, and a petite tapisserie dial on most examples. Because it shares so much with the 14790, plenty of watches advertised as a 14791 are really the other reference, or a blend of both.
That overlap is what counterfeiters exploit. They do not have to invent a watch. They only have to make a 36 mm Royal Oak that passes a photo.
The checks that catch fakes
- Movement. Open the back. A watch from this family should hold a thin, AP finished automatic of the period. What shows up in counterfeits is an ETA 2824 clone, a Miyota, or a quartz module with a decorative rotor bolted on top. Wrong movement, wrong watch.
- Case measurements. Put calipers on it. Modern fakes are built from a larger case and shrunk in the listing photos. If the numbers do not match the reference, stop there.
- Dial and tapisserie. The grid should be cut clean, with sharp corners where the squares meet. Fakes show soft edges, uneven spacing, or a printed grid instead of a stamped one. Look hard at the AP monogram and the font of the signature.
- Caseback engraving. Reference, case number, movement number. Check the depth and shape of the stamps. Flat, grey laser etching gives away a modern case. The numbers also need to match what AP has on file.
- Bracelet. It should be integrated, with the correct taper and clasp stamping. Aftermarket bracelets are common even on genuine heads, and they get sold as original.
- Hands and crown. Shape, finish and lume should match the age of the dial. A dial that has aged forty years next to hands that look new is a warning sign.
Why this reference attracts frankens
A franken is the harder problem. You can have a real case, a real bracelet and a real movement, with a dial that left the factory on something else. Or a genuine 14790 with a 14791 stamp added later to push the price. Nothing on the outside resolves that. The archives do, because AP records what left Le Brassus and when.
Price sanity
Vintage 36 mm Royal Oaks trade for real money. A listing at a fraction of the going rate is not a bargain, it is a warning. I also want service history if it exists, and I want the seller to name the watchmaker who last worked on it. Vague answers about provenance are a pattern, not a one off.
Bottom line
Assume nothing from photos. Confirm the movement in person, measure the case, read the engraving with a loupe, and let the Extract from the Archives settle the rest. A seller with a real 14791 will welcome all four steps. A seller with a fake will find reasons to skip them.