I have the dravidian and gurjara achievement without owning the DLC and i havent played the campaigns. Not sure why. I think one of them even popped up after a loosing game, where the enemy had that civ. So something seems bugged.
To make it even more funny: My best civ according to my ingame profile is Gurjaras. Again: I havent played that civ, since i dont even own the DLC.
Dont ask me how this is possible. I dont know either.