I fly PDX-KOA frequently. Almost always the flight starts out showing a 900 or a Max 9 with only 12 first showing on the seat map. As you get closer to the flight date and Alaska is reasonably comfortable they will actually use a 900 on the flight the seat map will start to reflect 16 first. If the flight starts out showing a 737-800 with 12 first you can be concerned there is a good possibility of the flight actually going out with 12 F seats.