No representation is made by GDYNets as to the correctness of this information, or its source.  Where I procured it was from a ongoing discussion on the Cadillac-LaSalle Club forum; which I recently revived after a 3 yr. dormancy.

To appreciate, precisely what is being discussed, please see the picture below:

Note the area of the tag which has been circled in red.  First off, let me state, this body data plate is not from The Gray Lady.  However, it is similar.  In the circled area The Gray Lady actually has a letter "R."

The question is, what does the circled letter mean?  Why is it there?  What purpose does it serve?  If you have any information to contribute on this topic, by all means share it with us!    EMail Dave 

Here is what I have been told:

The "R" on my tag stands for "Radio."  My problem with this opinion is, it does not make a lot of sense.  Since every 1955 Cadillac, to my knowledge, came with a radio as standard equipment, why would any code be needed at all?  It would serve no purpose.  It did not inform the assembler, "Put a radio in this one,"  since every car rolling down the line had a radio put in the dash.  [NOTE:  I have subsequently learned, much to my surprise, that a radio was a Cadillac option in 1955.]

Codes  in this area of the Body Data Plate that I have actually seen, or have been informed of, are E (above), I, M, MM, N, R (mine), S, T and U.

I have also been told the "E" stands for E-Z-Eye Glass.  This too is illogical, because "E" is one of the codes listed for ACC(essory).  That is readily seen from the tag pictured above.  The ACC codes there  are EHY.  I can see no reason to have the same code twice on the body data plate?

Another problem with these opinions is that it assumes the body data plate was consulted by the assembler during the build process.  That is doubtful, given the fact a build sheet was readily accessible on every car coming down the line.

It would really be great if some retired Cadillac autoworker, who was there at the time, and actually knows what these codes were used for (if anything), would educate us! 

The code in question refers to the color scheme family.  It was used at assembly time for line workers to know what color trim and accessories items should be placed on the car.  By way of example, for my car, the gear shift knob is gray.  When the person responsible for this part of the assembly saw the "R" on the data plate, he knew to install gray colored accessories/trim.  Assuming this is accurate, all cars that came off the line with a gray color scheme would have an "R" code.  Other cars would have other letter codes.

Thanks to Lou Commisso of Cadill-Ikes for the answer!