The Mozart, the smallest format in the Meisterstück range, was indeed available as a Solitaire with a line guilloche in vermeil, that is, gold-plated sterling silver. Later the same version was offered with gold-plated copper as the base metal. As this is a regular production model and not a limited edition, there is no edition size: for standard writing instruments Montblanc publishes neither quantities nor exact production periods. The range was built over many years, and pens of this kind could still be found in the specialist trade at the end of the 2000s. The simplest way to tell whether a version is still current is to see whether it is listed in the manufacturer's current collection.
The strikingly tapered shape of the rear end of the barrel is not peculiar to individual versions but follows from the design: on every Mozart the cap has to screw onto the back, because without the cap posted the pen would be too short for most hands. Collectors' websites are far from showing every variant, so the absence of a photograph says nothing about whether a particular version exists.