Yes the Rolex boys do it....and you remember the spate of grey telemetre speedmaster bezels last year? I suspect they might have had help.
I have not tried it. My Rolex friend tells me that you have to check the reverse of the insert which should be a darker colour as it is not exposed to the fading influence. Be it light, UV or environment.
Where upon he flipped the bezel off his watch and clicked out the insert - something we speedmaster owners cannot do so easily. Speedmaster inserts by themselves are not service replacements, only the entire bezel. Once a bezel insert is separated from the steel ring it is hard to get it to stay back without glue. (In my experience).
All these little tricks the Rolex boys have used for years I expect to infect our world as prices rise.