From the fountainpen.de archive
Counterfeits of the Solitaire with guilloché
The Solitaire copies frequently offered on internet auction platforms, mostly passed off as an Anniversary Edition, deviate in part so strongly that the differences are noticeable even in poorly made sales photographs.
In the overall view the cap bands of the copy are interrupted by black rings, and the guilloché sits markedly more closely together than on the original. On copies the cap top is often entirely black, that is, as on an instrument made of precious resin; Solitaire writing instruments always have a top there in the metal finish of the body.
On the cap star the copy shows an angular shape that tapers to points at the corners, whereas the original star appears rounder and markedly whiter. The clip of the original is rounded, that of the copy sharp-edged and angular. In the side view the serious difference lies in the clip ball: on the original it is attached separately, that is, soldered on, while on the copy clip and ball are bent from a single piece of sheet metal, so that one can hardly speak of a ball shape at all.
A particularly reliable feature is the marking on the clip. The serial number of the original is burned in with a laser and therefore always appears grey; on the copy it is embossed or stamped in. Any marking that looks as though it had been pressed in belongs to a counterfeit.
Source: Comparison report, original versus fake · Original issue as PDF › · Photo comparison, original versus fake ›