Rotors

I was wondering if someone can tell me when you are doing rotors does it come with the hub and the studs or do you have to switch the hub and get new studs?

Years ago, back in the day, when you bought a rotor, it was sold with a hub.
That's the way it was done back in the 60's, 70's, in the "old" days.
Then for whatever reasons, probably for such a small market, rotors became obsolete from the manufacturer's.
Once the old supply was used up, you couldn't find them anywhere.
Then A few years ago, one or two manufacturer's started making them again.
But they are Rotor only, no hub.
That's why you can't find HUBS in this modern day and age.
Back then, they were just thrown out still attached to the junk rotor, knowing you could still purchase new rotors that came with hubs.
There was no reason to save hubs, in the old days.
But be thankful that at least rotors are now available to rebuild these Kelsey Hayes brake systems.