Yep, knuckle out including the spindle and brake brackets. Chev is easier if you have access to the parts. Chevy you need from the spindle out and the brake brackets circa 1977 Blazer (as I recall). There's a couple more things to consider too with the chev stuff. Chev axle stubs are a little longer (because the spindle is longer). You can use your stock bronco stubs without the snap ring, drill them and put a big washer and bolt in the end (I've done that, it's no big deal) or swap on chev stubs. Your question about does it just bolt on?.. yes but, Ford changed the bolt pattern on the knuckles when they went to discs, so the Ford Dana 30 and drum 44 are usually swapped with chevy. You'll also need a disc/drum proportioning valve. Like Mitch said, the Chev stuff is getting hard to find but even new spindles are pretty cheap.
-Steve