Using your description the "curve" faces the driver.
That little "curve" bends around the relief on the kick panel at the pinch weld. The welded nut goes up. The Sems washer bolt also points up.
And you don't install those brackets until the dash is already hung in the Bronco...and they go in last. Don't be tempted to put the brackets on first and try to pivot or hang weight on them.