Factory disc brake rotor question

I bought a fairly complete factory disc brake setup. Came with pair of spare rotors that have the hub removed. I also found a bag with used KH wheel studs.
7/16" fine thread. They appear to match the other studs that are still attached to the other hub/rotor.
So I go to drop the stud in the rotor and it slips right in? No press needed?
The reason for the question about tack weld on the back was we had to do that to a rear stud on the 67. Spun a stud, so there was no way to get the tire off. 2 man job, 1 to hold stud from spinning and another to get wheel nut off. Make sense? Hope I explained it properly.
If I encounter any of those fn LH wheel studs, they will be replaced pronto. I've ordered Timken bearings for them. Timken SET2, and Timken SET6 are the #'s. $11 each, pretty good.
Seal is also a Timken, crosses from a National # I got off here #6840S. $17!! each damned seal!
Front drums appear to be 10". I wont ever use them. They will go with the car if it sells. I havent done a lot of research but I thought I read the hubs will swap between disc and drum?
I'm gonna blast the other empty rotors for a look see.
Oh and found another pair of hubs, not sure what from? KH stamped in them.
Thanks again

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