They (the Russians) also copied the US-6 truck up into the 1960s. There was a very bad flaw in the cab area of the US-6, Studabacker know about it, but the military would not let them correct it due to it would mean stopping production. When the Russians started copieing the US-6 after WWII.....they even copied the flaw in the cab.
Years ago, I wrote a story for Army Motors (MVPA) about finding some US-6s here in North Carolina. They all marked as being used on the Alaskan highway during 1942!
One more note on the US-6, it was not like the CCKW as far as carrieing wieght. The US-6 was more like the M35 on being heavy duty. The CCKW was more on the light truck side, she had a very weak clutch, and could not carry nearly as much as the US-6, or the International 6x6. The good thing about the CCKW is a they made a bunch of them to move the goods.
One of the few, Frank USMC RET