TTB
62 K won't be made available for pre purchase on most routes. In my experience the Upper Deck is reserved for full fare payers & Gold card carriers.
I tried before well before our Christmas flight to CPT & although there were empty seats upstairs they wouldn't allocate one. When the strike was called & I brought our flight forward by a couple of days in order to avoid the IA I was suddenly allowed access to a couple of Upper Deck seats, even thought J was full.
Basically it's a very complex situation.