I would think this would indicate positive cabin pressure and no structural damage. How about the recovered stabilizer; what does that tell us?
There was nothing in the ACARS messages to indicate that cabin pressure had been lost, but rather to the contrary, i.e. the aircraft was descending at a greater rate than the cabin pressure controller could cope with. On impact the cabin pressure will have been less than the outside pressure, which would have caused a small implosion in conjunction with the major impact implosion.
The Vertical Stabilizer told us that it had left the empennage as a result of the tail impacting with the sea surface, as both compression and tension damage was observed.