With regards to RL polos, I believe that they are all fakes, except if you to go a RL outlet or a department store. In AUS, RL polos retail for up to $119.95, but can be bought on eBay for less than $40. Common sense will tell you that they are all copies.
But having said that, I've just received a large shipment of RL polos and will be listing them (from a supplier who claims to be authentic). They do sell well and some of the copies are quite good.