When you remove the springs, take a good look at the bushings in the main leaf where the spring pins fit. If they are worn you will need to have them re-bushed. My fronts were worn past the bushings and into the leaf itself. In that case you will need new main leafs.
If they look good and the truck was sitting level, I would re-finish and re-use the springs.
Others may differ but I have never had any luck with re-arching. After a time the metal will sag again. Most times, for the price of dis-assembly and re-arching you can buy a brand new set of springs.
