First off there are a number of factory two tones available for your car...depending upon when it was manufactured, it could have the 55 colors on it. It is my understanding that the the later models, those with the automatics etc and maybe even all forward of that introduction date had the 55 two tones. My car is one of them..it is factory color and not in the standard 54 library you see most chip charts illustrate.
There are as many color schemes as their is imagination I guess..however the standard two tone was inverted colors of light blue top, dark blue bottom then flip that for the other..this was offered flip flop top bottom of the schemes. Again, late models could very well have the 55 two tones which are more varied and prettier colors.
Top...belt line and above
Bottom...below the belt line...
Any combination you wish in between with even a solid color top and bottom with the area between the beltline and the drip rail contrasting..