72ChevySS

My buddy has a 04-06 silverado ss awd. I love the truck but it's rusting pretty bad on the front and rear fenders above the wheel wells and on the rockers. I want to help him get his truck looking A1 again. Just wondering if I can just go to a junkyard and pull fenders off any silverado from the same body style or are there differences? If not any recommendations on sites for body panels? Not trying to break the bank but want to help him out. Figured you guys would help me figure out a direction to go.