PPG store has color chips for oem colors on new cars that are a range so you can pick the one closest to what you have. It may need to be tinted slightly if your picky.

Also if you want to use clear coat but not sand it as much let the painter know ahead of time. Most guys pound that stuff on thick as they plan on sanding a few mills back off to get it super smooth prior to buffing. They will care more about avoiding runs and dirt if they know most of it has to stay on the car.