^^^ How would they be able to fire when the time arises, if they are concealed?
They wouldnt need a shield for Hyperspace (as some poeple have already pointed out.
And they would need a really big and powerful shield generator on board.
But, that wouldnt seem a big problem, what with the size of the DS and the power magnitude of its superlaser.
And in referrence to the "fully armed and operational battle-station" i'm pretty sure Palpy was referring to the superlaser. That was operational, and with the fully armed part. The shield generator down on Endor seemed to be pretty powerful to opertate something as huge as the DS.