Yes, its the JB8 code calipers. They are the clip style and the trouble I had was with some castings that I got from the local auto parts store had an issue. They had material added and then machined the surface and it was a poor job. I went to NAPA and bought a set and they went on but if you aren't familiar with them, they can be a little tricky. As far as the spindle not fitting, I had no problem. They bolted right on to my ball joints with no issue. My truck is a 72 but I have no idea if the control arms had ever been swapped out with later model ones, I do not believe they have been. I sourced later model dually rotors as mine were pretty worn and the new ones had a good 1/4" of meat on them and were off a truck with the JB8 brakes. got them turned and put new bearings in and they slid right on. I have not driven the truck but around the block because it still needs other work but it does stop real good from 25 mph now
I hope this helps. Shoot me a message if you have any other questions, I'd be happy to lend a hand.