What is the difference between rust and pitting? Is there a visual or other way to tell? Is there any kind of "test kit" that can tell you if it is just rust or pitting?

If something is indeed pitted, I assume there is no way to restore?

Lastly, does the spray on re chroming work? I saw this on a video of Jay Lenos garage and it looks like it worked? Does anyone know the name of said product, cost and if it indeed works or not?