Haven't used it myself, but looks like just about everything you'd need. Don't see why you'd need new locking hubs though. Should be exactly the same as what you're running now. They were all the same on those trucks anyway (Ford and GM and some Dodge and some Jeep), but those should be Ford hubs they're using anyway, so it's an exact retrofit for the lockouts.
Only issue some people run into is the outer snap-ring on the axle stub may not work, as the existing Bronco stubs may not stick out that last 1/8 of an inch or so.
That's about all I can think of at this point. You'll still have to do the usual grinding of the knuckle to clear the new calipers that any other GM kit might need. Hopefully they'll say that in any instructions that they provide.
When the price is corrected for the calipers and any shipping, is it a better deal than the Bronco vendors offer? I haven't looked at their prices lately, but thought I'd ask just in case you hadn't checked there first. Nothing wrong with an eBay supporter of Broncos too of course, but I like to check them out, and for eBay at least, that $395 doesn't exactly sound cheap.
Maybe if they're closer to you than some of the other vendors though, shipping might be a benefit.
Paul