Not sure they have been bolted as sport routes, but bolt belays have been placed on some routes which seem to be the main concern.
There are other examples of these basalt columns in Armenia, it is just that Garni Gorge seems to be the only place they have been developed for climbing. I am planning on having an explore near where I will be working for the week, and may try get to check out the non-basalt column venues which I have been sent information about...