Nice to see the "hammer" (Czech denomination is "Kladivo") here and there built up nicely! Only thing I can't really figure out is this three-tone-camo, though... As far as I see it, the AM2Bs were painted in plain "chlorbunagrün" and of course with NVA markings on the turret sides...
They were ordered by the GDR because of price reasons. To update their existing T-55s to T-55AM2Bs was MUCH cheaper than to buy brand new T-72s (even though NVA fielded those as well but in much smaller numbers) from the Soviet Union. I believe the updates were performed in Czechoslovakia (back then Czech and Slovak Republics were still united) because they were holding licenses for T-55 production and GDR had contracts with them concerning the T-55 and Tatra orders... Czechs got the GDR produced Trabant in return -> good deal, eh!?