It seems like the consensus is that there isn't actually a problem here.
At lunch I went back to the same dealership I was at yesterday and looked at another 45th Camaro. There was sunlight out today so I asked a salesman to pull it into the sun, so that I could see the reflection off of the door. I pulled my car behind it so we had angles on both doors reflecting the light.
I swear we looked for 10 minutes and he could see the color variations on my door, but could also see them slightly on the other Camaro. I looked at both and at times I thought I could see them slightly on the other car, but then when I looked at my car, I couldn't really see them that well. About the time we started looking the sun went behind a cloud, which is not helpful at all.
I don't know if my eyes were deceiving me or not, but it looked like the other car had a similar blotchy effect to the paint in different lighting circumstances, although not as prominent as what I see in my car. The salesman didn't think anything was wrong with my car, but I still would have preferred better light so I could get the worse reflection off of my car and compare it exactly to the reflection of the other car.
At any rate, it sounds like at this point I should forget about it and move on and that it is very possibly happening to other copies of my type of Camaro. It is weird to walk out to my car occasionally and see the blotchiness in the right lighting, but I think living with it is probably the easiest solution at this point if you guys truly believe the PTG readings point towards this being factory paint. Plus seeing that other GM metallic paints have had similar effects on other cars puts me at ease.
Still though, kind of a befuddling concept: if the paint on the car is factory paint, I'm okay with the imperfection; but if the paint on the car is not factory paint, I'm not okay with the imperfection. Either way the imperfection is the same. Oh well. Better to get over it then to obsess about it.
Thanks again for all of the responses.