I'd fire this question off to the folks at Eminence. You'd be surprised how unassuming they are and how willing they are to discuss matters like these. For example, I asked about ferrofluid treatment of the PSD2002 and they told me that the stuff evaporated but that they had, in fact, done comparitive testing of their drivers with and without ferrofluid.So they may very well have measured a PSD2002 (or an earlier model) with the back cover removed to see how much effect there is. And honestly, I would expect this from them in order to confirm the response with the system having its specific back chamber volume.
If you do write to them, I encourage you to tell us what they say.