As I recall, my drums were attached to my drums by swedged metal. I. E. metal that is smashed into place around the lug bolts to hold them in place. You can see the squiggly line around the lug bolts in these pictures.
Those are the swedged. swedged lug boltd
I'd never heard of a swedge before but to remove the drum from the hub a swedge cutter is used to cut out the metal around the lug bolt to a depth of about 1/8 inch deep. If you try to drive the lug bolts out without using the swedge cutter you'll ruin the hubs. Some machine shops have the swedge cutter. They are difficult to find on line but they are just like a hole saw. Come to think of it, I think I cut the lugs off since they'd be replaced and I drilled out the center before driving them out. Make sure you don't touch the hub holes because the new bolts have to fit in the hub very tightly. If in doubt, take it to a machine shop. If yours are just riveted then I think you can drill them out and the disks will stay in position once assembled without the rivets since they are smashed between the wheel and hub by the lug bolts /nuts.
With the hubs removed from the drums you can order the tapered bearings if you wish and have the old bearing races replaced with the tapered races and you are good to go. The CCP kit comes with new lug bolts that you can install in the old hub by sticking them through the hub, and using a stack of washers under the lug bolts, tighten the nuts to pull the lug bolts through the hub. It's a super tight fit so alternate from one lug to the others in a cross pattern until they are pulled into place.
One last thing. They recommend that once you have the hubs and disks mated, take them to be turned on a brake lathe to true them up. Mine were slightly out as measured with a dial indicator but I can't tell that they aren't perfect.
It sounds like a lot but it's all worth it and really not that difficult if I could do it.