Cut a lengthwise slit down the center of tenderloin to within 1/2 in. of bottom. Open meat so it lies flat. Place on a rack coated with cooking spray in a broiler pan. Sprinkle with salt and pepper. Brush with 1 tablespoon barbecue sauce.
Bake at 400° for 15 minutes. Turn pork; brush with 1 tablespoon barbecue sauce. Bake 10-12 minutes longer or until a thermometer reads 160°.
Cut into 1/4-in. slices. Spread remaining barbecue sauce over cut side of bun bottoms;layer with pork, coleslaw and pickles. Replace bun tops.