If you were a new car buyer in 1956, you had the choice between 20 different 1956 Buick Colors. Not all of them were available at the production start; these five colors were added throughout the year: T (Bitter Sweet), U (Apricot), W (Spruce Green), X (Nile Green) and Y (Mist Green). Do you recognized some of these colors? Yes, they were introduced in April, 1955! Means: They were so popular, that Buick re-introduced them after cancelling them!
The general paint indication was continued: Three letters indicate the three paint areas, roof, body and below the sweepspear. If you look at the body tag from your 1956 Buick, the first alphabet letter designates the upper color, the 2nd alphabet letter denotes the center color, and the 3rd alphabet letter denotes the color below molding, i.e., Combination AAA would be all Black, and ADB would be Upper – Black, Center – Electric Blue, and below moulding – Castle Grey. AAA-1 would be a solid black car with the optional red wheels.