If the original skin was pre-punched, I?m betting you can just drill the holes in the new skin to size, debur, and dimple and it would match perfectly. I had to replace a forward side skin on my RV-8 before removing the ?canoe? from the fixture and it matched up very well. That included the seemingly hundreds of holes in the landing gear box area! The reason I had to replace the skin is because I had an air hose failure that put a large outward dent on the skin.
All that said, I agree with Dave. The parts are inexpensive, especially since you will already be paying for shipping for the skin. Also, it is likely less effort to build a new rudder than it would be to drill out all of those rivets.