Don't know if you are still considering replacing the knuckles, but I have a pre-2003.5 or whatever it was (the smaller one) that was incorrectly installed on my 05 FX4. You can see it in some pics in this thread: FX4 Level II -- wrong kunckle!!??
I don't need it anymore, and if you'd pay the shipping, you can have it. I'm tired of it sitting in my garage. It's only the front left, of course, but that gets you half way there. You'll be happy to know that everything else like the calipers, pads, hubs, etc... are all the same. The only pain the butt was getting the hub out, but even then if you follow the suggestion of putting the bolt in the back (see above thread) it wasn't too bad.