The one they showed us in San Diego was clipped to the cover, so yeah, you can do that. The only fixed contact between the cover and the Reader is that round thing in the middle of the back of the Reader.
They were clipping it to front and back cover both, to keep them together.
In my own experiments, I've found that clips where the end of the clippy part itself turned up made me worry about scratching the Reader housing or the other part of the cover, so you may want to consider that.
