Sawmill,
Step 1: Carefully grind existing screws flush to the bolster.
Step 2: Carefully center punch the screws.
Step 3: Mark a #25 drill bit about 5/8" up from the tip by wrapping with a bright colored tape (i.e. masking tape or electrical tape).
Step 4: Carefully drill out the "offending" screw.
Step 5: Carefully chase the threads with a lubricated 10-24 tap using a manual tap holder. The left side (looking from drivers seat toward front) is easy. The right side is a challenge. The front screw is difficult. The rear screw can only be done with a long tap.
Take your time and you'll be fine.
Peter