horizon blue might have been a car color - it was not a 1954 Chevrolet truck color
Were you looking at a 1954 Chevrolet car color chart?
Light Blue is in the Bulletin (above) - that would be the Transport Blue
Dark Blue would be the Mariner Blue
Check the 47-55 Truck Colors Tech Tip for original truck paint chip sheets/name/codes.
Note that paint chip colors have been changed by age (as have been the colors on the truck - changed the least, as you point out, in areas not exposed to light/air/wet).
Tim, the transport blue and Mariner blue are not the interior colors. What they are saying is that the two tone blue interior was available with either the transport blue or the mariner blue as exterior colors.
As far as I know, there were not names for the interior colors. I had my two interior blues "scanned" before I removed all paint from the cab. Another member used my formulas and had at least the lighter blue mixed up and shot. He sent me a piece from the bottom of the paint gun and it was a very good match. Jim Carter sells the interior colors but my experience has been that his lighter blue is a little too gray. Close but not quite a match to what my truck was originally.
