Yes, I would agree that this is certainly possible, if not even probable (we won't know until we know). The thing is, I nonetheless doubt that any civilization will ever build a Dyson sphere because there are almost certainly far more efficient and refined ways of getting energy, and that's the conjectured purpose of a Dyson sphere. We may very well be able to pull energy right out of the vacuum before we get to the stage where we could build a Dyson sphere..
The Dyson sphere is old tech anyway. The three levels of civilization that Dr Kaku usually mentions on his Coast talks classify civilization by the power they make available for their use. If they are at the level of a Dyson sphere they are just beginning to emerge. We are not yet at the first level, being little advanced beyond wild apes eating berries and leaves.