Actually the Kings can end up only 2 or 4 seed. They also control their own destiny.
A win by the Kings assures them the #2 seed.
A 3 way tie (Spurs lose, Kings, LA win) would result in the Kings being #2, Lakers #3 and Spurs #4.
A loss by Kings puts them in the #4 position. If LA loses also the Kings are back at #2.
On another note it is only the second time in NBA history that every team in a division finishes with a .500 or better record. All hail the Mighty Midwest.