It's not a Leica copy, the compoany had access to Leica tooling as part of the War reparations (after WWII). It's the only camera based on a Leica that's better made and later Leitz had some lenses made for them by TTH (the ownwers of Reid and Sigrist). They were based on later Leica's not the IIIa - I can't remember which model off-hand.
At the time the TTH Cooke optics for the Reids were significantly better than Leica's own lenses.
Some of the early Russian "Leica copies" are made using machery and tooling taken from the Leitz factory.
Leica/Leitz was anti Nazi and had helped many Jewish empoyees escape from Germany, they also hid their prototypes for the Leica IV, Reid launched their cameras which were highly aclaimed, butb Leica then released their M series with the M£ and better lenses, a bayonet mount, all trialed in the pre WWII IV prototypes.
The M series Leica's killed sales in the Reids.