It used to be that different maps had different models for CT/T. In dust 2 the CTs were the IDF, for example. Likewise there were western Ts too, like the Anarchists in Office.
I don't know if they'll port them to CS2 or not, will be a shitty move if they don't.
I'd rather they skip or replace the IDF, but I want the rest of the models back, it's how the game was when I started playing it and it adds some variety. If they don't add them, it will be an obvious move to increase sales of player model skins ("agents") you can buy on the steam market.