These uniforms were not intended to be used in Central Europe during summer despite their name. They should be used just for missions abroad. As the Czechoslovakia ceased to exist soon after their adoption they were soon replaced by national camouflaged uniforms in both woodland or desert camo.
First model - stamped 1990 (or maybe sooner). It was used during Desert Storm, trousers have reinforced thighs and knees and they have thigh cargo pocket with covered buttons.
Second model - Stamped 1991. It didn´t make it into Gulf war soon enough but they were used in peacekeeping operations in former Yugoslavia. Trousers have reinforced thighs and knees. Waist pockets covered by flaps with exposed buttons and thigh cargo pocket with exposed buttons.
Third model is the most simple one. I don´t know about the stamping or usage. Trousers didn´t have reinforcements, nor the flaps on waist pockets. Cargo pockets had flaps with exposed buttons.
Here are pictures of second model I recently bought.