I would still lean with Oscar Smith in this one, but it will not surprise me at all if King's Fork wins. I went on record in the summer saying that King's Fork is the most talented team in the Southeastern District, including Oscar Smith. The Bulldogs have a scholarship level player at every position on the roster.
With a win, King's Fork grabs a #1 seed for Class 4, Region A. With a win, Oscar Smith secures no worse than the #2 seed for Class 6, Region A. But the Tigers could even vault to the #1 slot should Cox upset Landstown. I know, not likely. However, Cox does have junior sensation Tayvion Robinson (20 touchdowns 5 different ways this year, including 3 pick-sixes). Furthermore, Cox has won every meeting with Landstown dating back to 2011 by an average of 23 points per game, so it is possible.
So to answer your original question - if I had to put a percentage on it that King's Fork wins, probably something like 35 to 40%. That may not seem like much, though it's a lot more than most teams Oscar Smith plays.
The status of injured RB Deangelo White for Oscar Smith could be key. I'm also interested to see whether they stay with Dominique Brooks more at QB or Cam'Ron Kelly, their terrific junior talent with offers from many of the major college programs out there (Alabama, Clemson, Michigan, etc.) at DB. King's Fork has two superb d-tackles in Treyshaun Mitchell - younger brother of Ohio State bound LB Teradja Mitchell - and Jayree Hardy that can really disrupt things up the middle.
What swings it to Smith to me is their big-game experience coupled with King's Fork sometimes being a bit mistake prone - whether it's through penalties or turning the ball over in the air. That Oscar Smith defense is extremely tough and RB Darran Butts of King's Fork will have to turn in a big performance for them to win at home. Possible, just not probable in my eyes.