It all depends on how extensive your restoration is going to be. If you just want to drive it, I would try to free up the grease passages to get grease through them. Back in their day hardly anyone replaced spring bushings because nothing really bad happens if you don't. If you are working on a larger truck, it might be difficult finding parts. If you break something while trying to take it apart, you could create a problem. I'm sure your truck will never see hauling loads every day. I would clean up as much rust as possible and paint and drive it.