Most likely candidate would have been one of the ZIS-5 series of 3-ton
trucks. They're 4 x 2 but the most common medium truck in Russia in
that time period.
Fort/SDS/Eastern Express (and whoever else has the molds) has a
simplified but easy to build one; Alan and Zvezda/Italeri both make
more complex kits, of which the Zvezda one is by far the better of the
two. Zvezda even throws in a nice driver with handlebar mustache!
Cookie Sewell