I know two piece shafts need to be shimmed, but to the Moser Engineering 1 piece shafts need to be shimmed as well? The people who have installed them said they do not recall ever needing to. I do not have directions or any information on them, where already installed with vehicle.

Contact Moser, they'll have the most accurate info.
I have a Jeep model20 which I put the old Durablue 1 piece shafts in and they came with various size shims to preload the bearing.

Eah I know for sure they do now. Bearing burned up, again.