There should be little or no color variances from panel to panel but.... These cars are not painted like a "regular" car. These are panel painted. What that means is that Hoods are painted and quarters are painted and doors are painted all off site from the assembly facility and the parts are sent to the assembly plant. During assembly the car will get assembled with a blue door, and blue hood, blue quarters etc... normally a car is painted as a single unit separate from the previous and the next car. Our vipers are painted in batches. If the hood and the door were painted on different days, or even morning and evening, the humidity and gun pressure, temperature can all contribute to minor panel differences. In addition the way light will hit the metallic on different panels can influence the appearance of panel mis-match.
If the tint is only slightly off in some specific lighting conditions, I wouldn't worry.