What do the Rolex model alphabets represent?

Model number may have alphabets behind them. Example “116713 LN” , these alphabets represent the colours of the bezel.
The common alphabets are LN, LV and LB. Which represents, Lunette Noir and Lunette Verte Lunette Bleu respectively.

Lunette=bezel
Noir=black
Verte=green
bleu=blue.

Some bezel may have 2 colours and are represented as:

BLRO (Bleu/Rouge): Blue and red bezels found on GMT-Master I/II

BLNR (Bleu/Noir): Blue and black bezel found on GMT-Master II

CHNR (Chocolat/Noir): Brown and black bezel found on GMT-Master II watches😎