The WWII 4BO was not used after 1947. if I am not mistaken, the color was changed again in late 1950s.
But according to many modelers "you can paint your Soviet tank in any shades of green you want". Just look at the Russian armor category in modeling show. It looks like a produce section in a supermarket
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If you REALLY need to know, I can ask Alexander Akanihin (the AKAN owner). Maybe he can help.