67 GT500 4-Speed Tag

[texas swede]

Good morning guys,
Hope you are doing fine.
Have a question:
Can any of you tell me what a typical 4-Speed transmission
ID tag says or better yet a picture.
RUG? what letter(s) after the RUG
My car was assembled at San Jose in the end of January 1967 
which means the trans was assembled sometime in Nov-Dec 1966.
Thanks for your help.
Texas Swede

[The Going Thing]

RUG-S
Here is a picture of a tag.

[texas swede]

Thank you very much.
Texas Swede