We have been on the Sky, but in neither of those cabins. We have been in M727 and M726 on both the Regal and Royal. On the inside, the white space was the steward's closet. On the out side the area was split between the two cabins as balcony space. These two cabins don't exist on Sky, as that's where the Wake View Pool is. Find a picture of the aft end of Sky to see if there is anything there.
I see you were on the Nordic Empress, we were on her to ring in the new Millenium. What great memories.