Just a suggestion... but I would have your painter paint everything in order... left fender, left door, left quarter panel, tailgate.... That way you don't have to worry about any paint mismatch. I've seen it before when you paint the left fender, right door, tailgate, hood, left quarter panel, etc... Also make sure he paints it in the position it'll be assembled in... fenders standing up, hood laying flat...
I like POR-15 too, I do pretty much everything in the cab from the seat bottom down and inside the all of the body panels.
Lee