Starting the body work and I need some advice. For the rocker trim is it best to fill all the holes and drill new ones when the trim goes on? It seems it should be that way especially for the fenders since the spacing could change. They be will repro spears.

Thats what im doing.

mine were in perfect shape so i left them, i did have to redrill the fender holes.

I would reuse the old holes, and if you have an alignment problem with the channel, redrill it fit the car. If the holes are a little hogged out, I'd just use the next size screws.