These armored cars can be at either side of the conflict:
K54 - Mgebrov Twin-Turret Armoured Car
K55 - Garford-Putilov Heavy Armoured Car
K60 - Izhorski-Fiat Armoured Car
K61 - Armstrong-Whitworth Armoured Car
But was the most widespread, in my opinion, Izhorski-Fiat
Only from the Bolsheviks: K56 - Putilov Half-Track Armoured Car
Also, two of the armored car were seized by the Poles.
Green - it deserters and partisans, who were hiding in the mountains and forests (which is why they are called "greens"). I doubt that they can be armed with armored vehicles. Although the Red partisans in Siberia - there were 10 "Reno" tanks stolen from Americans.