was based on an improved, 1962's single-stroke Leica M3 black paint model bearing S/N beyond 10599xx*.
Other minor variations/features (esp. those earlier production units) may exist.
I have also provided a simple illustration of a typical double stroke, early Leica
M3 version at mid section for comparison (NOTE;- there are combination of other features
to confirm and/or for verification purposes on version/model, even as minute as the
design of the camera strap eyelet on both sides (early DS M3 has triangular shape,
later models has rounded ears, etc.). Please also keep in mind that Leica offered
Factory Conversion Services, such as double stroke to single stroke, addition of
a viewfinder frame pre-selector and even modified cameras to accept Leicavit for
auto film advance mechanism etc., and they were even faked to make them look like
rare variants by 3rd party technicians. Hard to be a collector today, so traders
with good experience, as well as highly rated trading credibility & a little
extra premium may seem justified at times.
* Note: S/N for Leica M3:- 700000~1164865.
Collectors Guide, by