Each of the 3 represent the metal color won by an Oakley team athlete at the Olympics. There were probably at least 50 of each made with all the rowing teams and what not. I thought I added them to the big list but maybe I missed it.
The pair advertised through the eBay link doesn't appear to have the "Rio 2016" etched logo on the lens (it could well be there, an the pic just doesn't clearly show it). I would ask the seller for better pics and a close up of the lens if there is an etching.
The examples of the pairs that were issued to the winning persons/teams clearly has the etching on the lens