I have a 16710 which I bought with a black bezel. I bought a red/black bezel and was allowed to keep the old one because the 16710 could use 3 different colour bezels (black / pepsi and coke) and the owners could swap them around. They would have sold me 3 new bezels if I wanted them.
The point on the Nato is a well known security risk. Someone can take a steel bracelet off a Rolex and replace it with a Nato. Then they ask St James to for a new bracelet because the Nato is non original. Rolex have to trust that they are telling the truth.
The next day the old bracelet is up for sale. Big weakness in the system.
The big weakness in the system is you being allowed to present your personal thoughts as facts on the internet.