I personally cant see why not, it has pedals and based on a cycle, retro is derived from retrospective, and was used to describe a stlye of motorcycle in the early 1990s kicked off by the Kawasaki Zephyr, what retro referred to was in fact a modern machine, with many of the modern features that improve safety, handling, brakes etc, yet retaining as far as possible the styling of machines of an earlier era, in the case of the 1990s Kawasaki Zephyr, the 1970s Kawasaki Z1, since then there have been many more in the motorcycle market, so your moped may well be classic or vintage rather than retro............either way, its a nice example