Absolutely do not need one. I just got a 60th anniversary and it has front and rear. But I had a wrangler unlimited Rubicon and never "needed" the front locker for the wheeling I do.
Want one? Sure. I hold with the "why not" crowd. But if you want to get what you need only, you do not need...
Dumb question here, but I just bought a bronco. You apparently have had yours and are familiar with it. But I noticed the steering feels a bit odd and grabs when the lane keeping feature is on, which you may not have. Just throwing the possibility out there--Whoops looks like Badlands Blade was...