It's an original Leica to start with, there were no Russian cameras that closely resembled a Leica with a slow speed dial at the front. Japanese cameras don't get faked into Leicas, they have a value of themselves already.
Second, the slow speed dial and other characteristics are typical Leica.
Finally, it's really no use economically speaking to forge a black paint Barnack, they aren't that more expensive than a chrome one would be, if at all.
tells you more. I intend to extend that article soon.
Or, download a Leica Historical Poster
and zoom in, you can make out the looks of the real stuff pretty good.