I had tried that also. But I'm not even sure what to expect. The only visible difference on my site is that one or two blocks that had been on the right are now on the left.
My evaluation of whether it has been reverted or not is based upon those blocks returning to the right side. I am not even certain if this is a proper thought to be having.
css file has nothing to do with blocks, it does not restore blocks position to previous (original) state.