Well they can just as easily go from being blocked to being unblocked, so definitely cross your fingers!
I would imagine that having them blocked also prevents anyone from paying the MCE fee to sit there, so it's a little weird they would do this.

Someone ended up getting put into the blocked window seat--weird because the two rows in front of me don't have anyone in the middle or window and are blocked. There are 62 empty seats in Y and still fully empty rows.