With numbered limited editions such as the Skeleton 333, the individual number often gives the fraud away. If, months after a completed sale, the same pen turns up again with an identical number, the same pictures and virtually the same description, quite possibly in another country, that is no coincidence: pictures and text have been lifted from the old auction, and as a rule there is no pen behind the listing at all. Anyone who keeps a record of listings in their own collecting field will spot such repeats.
Other typical signs: the seller offers to end the auction early and sell directly; payment is to go through cash transfer services such as MoneyGram, with the buyer footing the fees and with no way of recovering the money once it has been collected. As “proof of authenticity” there is a photograph of a supposed receipt on which nothing but the company logo can be made out.
The most effective counter-test is to ask for specific close-ups that cannot already exist online — of the nib imprint, the serial number or the engraved edition number — and to insist on them at the camera's original resolution. Genuine sellers supply such pictures; fraudsters break off contact. The fact that the same account is offering other high-value goods proves nothing about the seller's good faith.