Rear End Question on 1968 Coronet R/T

[17WithaCoronetRT]

I just bought a 1968 coronet rt was coded to come with a 3:23 suregrip posi rear end and has a large yellow "D" painted on it at about center, can you tell me what this means? any help would be appreciated, thank you.
Tyler

 

[rrunner]

Sure it's a D and not a B ?

 

[The Satellite Cometh]

I dunno but that '57 Chev looks in decent shape in one of your pics. LOL.

Bring her back to life young man.

 

[696pack]

It means nothing that will mean anything to you. Likely just a factory shelve code for quick identification for the assembly line. Maybe IDed the gear ratio, Sure Grip/open rear, and body application fit. There are many code numbers like this on parts assemblies that unless you are doing a full blown OEM resto that will be judge don't worry about it.