Here is the best rocker replacement thread on this forum by a very talented fabricator. You do not need to be body and fender guy to do this, just follow the steps and you can also buy paint in a spray can color matched at Napa Auto stores that have a paint department. Even if you get a few runs that can be buffed or wet sanded to look great.
https://67-72chevytrucks.com/vboard/...d.php?t=271066