Make sure the gap from the fender to the end of the bumper is the same on each side.
One of the things that can happen is the cab can be set on the frame rails crooked (this is especially true with the regular cab, since it is so short in comparison to a crew cab or Blazer/Suburban).
That means the hood, which is attached to the cab, is shooting off to one side. In order to get the hood to look right the radiator support and front fenders get pushed off to that side.
The end result is that you have more tire exposed on one side than the other.
Since the bumper attaches to the frame directly it becomes a convenient place to measure from, to see if your front end is square, or skewed.
It might not be the case with yours specifically, but I've seen it enough times it should be checked.