It IS true that if the trunk lid is not closed all the way, then neither the spoiler or roof will move.
But I question something: the latch assembly and the sensors that tell the BCM that the trunk is closed are not part of the same assembly, as far as I know. That is, if you order the latch assembly, I don't think it comes with the sensor(s).

Do you have the old parts? Can you verify this? There is a sensor that tells the BCM the trunk is closed. And there is a separate electric lock/sensor that has to activate to securely lock the trunklid so that the top pump will run. Now, this sensor/assembly would not have anything to do with the spoiler - only the sensor in the latch area that tells the BCM that the trunk is closed will have an effect on the spoiler.

I am headed to lunch, back in a bit.