Codes for 1958 Seville

[Barry M Wheeler #2189]

Jim Verasster, our Museum Treasurer has a 1958 Seville he needs info on a code. The firewall plate has 50 B for the interior trim # and the letter J out to the far right. Does anyone have the info on what that code might be? I think he knows what the "50" is, but he'd like to know what the other letters are for. Thanks in advance. BW

[fishnjim]

All the codes can be accessed from the GM Heritage Center archive.   
There's some controversy on what those other letters mean, as they were used kinda differently at different plants.   Some are special designations, some are destination codes, group, etc.  I don't follow the Seville options, so someone may have better info.   
He can obtain for $ a "build sheet" for it from them also which will clear up a lot of questions.
They won't release key codes anymore.

[Ralph Messina CLC 4937]

Barry,

FWIW. The following is a quote I collected from some web site, possibly this one. It describes the mystery code as defining the color of the dash pad and paint for a particular interior code. The first name is the color of the dash pad.

“Mystery code 1958 Biarritz and Seville. Have you ever wondered what the mysterious letters to the right of the trim code on the body plate mean, here is an explanation. The first letter tells you what color it should be on the top of the instrument panel and on the lower instrument panel. The second letter tells you if there is air conditioning in the car. This is because it is another top of instrument on cars with AC. Here is a list of the letters and an explanation.
 Top of instrument Panel / Lower instrument Panel on a Biarritz
Trim code
10-Black / Olympic White Mystery code F
11-Black / Argent silver Metalic Mystery code H
12-Storm Gray / Argent silver Metalic Mystery code J
13-Andres blue / Biscay Blue Metallic Mystery code U
15-Copper shade / Coronado Copper Metalic Mystery code X
17-Tampa Green / Bimini Green Metalic Mystery code Y
18-Kiowa Red.DK / Olympic White Mystery code E
19-Kiowa Red.DK / Kiowa Red.DK Mystery code Z
Top of instrument Panel / Lower instrument Panel on a Seville
Trim code
50- Storm Gray / Argent silver Metalic Mystery code J
51-Black / Olympic White Mystery code F
52- Andres blue / Biscay Blue Metallic Mystery code U
53- Andres blue / Biscay Blue Metallic Mystery code U
54-Copper shade Mystery code X
56-Tampa Green / Bimini Green Metalic Mystery code Y
57-Tampa Green / Bimini Green Metalic Mystery code Y
58-Kiowa Red.DK / Olympic White Mystery code E
If the car has been equipped with ac from the factory since then the second letter is always a K.
Note that the first letter is equal to a Biarritz and a Seville if they have the same color on the instrument panel.
 Do you have a car with special order trim So and body no into the trim row. Then you have no mystery code.
Seville body 1 and two have no mystery code and it is in the ACC line EK so both cars were equipped with ac. On late cars, it always says ACC EHK ?? on those Body plates I've seen. I have also seen ACC PH, which is strange since P = Optional gear ratio could not be chosen on an Eldorado according to the 1958 New car specifications manual”

I make no claim about it’s accuracy. It’s provided as a data point of information.

HTH

[Eric DeVirgilis CLC# 8621]

Thanks Ralph. I often wondered what those codes were for.

 "P" = Plain Glass (not tinted a/k/a not EZ Eye). There were options installed at the Body Plant and other options were installed during chassis production. Only options installed at Body Plant appear on Body Tag. Items such as Air Suspension, Q engine and Limited Slip do not. 

[JV3RI]

Thanks everyone for the good suggestions so far.
I did obtain the Build Sheet from GM Archive.
Everything on the car that you can see visually and on the data plate checks out - except that mysterious B next to the 50 Trim Code.
I read the post that Ralph reposted about dash pad color - I wish I could understand it.  Maybe the B refers to the dash pad color ?  The original dash pad is the only component of the whole interior that is not there. Dang.
I will try to post the Build Sheet in case anyone notices something there that I don't. Hope everyone is staying safe. Jim Verraster.

[Ralph Messina CLC 4937]

If this is the same car that’s in Lars Kneller’s post, the “J’ indicates the dash top was Storm Gray with the lower dash painted Argent. The note I posted refers to a letter to the right of the trim code not part of the code.

FWIW, I have seen trim codes in the MPL where the numeral and description are the same but there’s a letter attached to one. I’ve been told that it designates a slightly different cloth. Usually something is different in design  because of production method or a different manufacturer. In such cases the fabric appears the same until they are side by side for comparison. The letter was to alert any technician to that fact before repair work began. I was told this by a Cadillac Parts guy but have never found it in official Cadillac publications