Rebush them and install, you can paint and prep them, but the paint will wear off and get dirt over it, with lots of road use.
Best install advice is to use 2 jacks. It's best to keep it out of the way as fighting the 'arch' of the springs and the weight of the axle is a good way to have an bad accident. use a shop jack to pin the rear axle to the underside of the car above the springs. Install the rear hangers, use a smaller car jack under the arch to 'flex' the spring and use a large screwdriver or pry bar to "position" the studs though the forward body mount, if you can get one flange nut on and tightened the rest will follow. Once all the bolts and nuts are secured, drop the axle on the centering stud on the perches, install the plates and U bolts, then jack the axle back up to install the shocks and brake flex line then the driveline. Bleed the brake lines, reinstall the tires and then you can move forward to the emergency brake cables then put the car on the ground.
If you do it right, you won't need assistance.
-D.Idiot