The spindles are different on the old axles compared to the newer axles which disk brakes came from so some sort of adapter will be needed. My kit uses a Ford inner wheel bearing on a custom made spacer/adapter, and a stock GM outer wheel bearing. The disk rotors and I am sure the drum brake hubs all use a bigger inner bearing so you will need to machine or buy the adapter. It doesn't make much since to adapt all the parts and still end up with drum brakes. With a closed wheel, you can not see the rotors unless you are under the truck looking. The open driveline has already removed any originality so disk brakes won't matter much. You can always claim it was a special order option, 99% of those looking wouldn't know the difference.
Check out the venders for brake kits, they should show what all is needed to do the job.
Joe
