And, of course, it's all completely academic if there are no more seats left that fit your preference.

Take, for example, the WT+ flight that the OP is booked on in December. There are 7 window seats in that cabin (super hi-J 747). Two are bassinets, two have been taken (each by half of a couple, it seems). And, of course, the other three are prime targets for any other couples who book, as they would naturally gravitate towards window-aisle pairs. Once they're gone, they're gone - and specifying a window seat preference won't do even a Gold any good.