GW Forgiers?

I was going through my Skaven last night and noticed that about 30 of the clan rats (old style) and Rattling Guns are a odd white plastic (resin) look to them... this was out of a lot I picked up about a year/two years ago but just now noticed this.. posiblly was an e(vil) bay purchase... Was/Has this been an issue where someone just copied a bunch of GW models and sold them online? When I researched it some I found a you tube video on how to create molds outof existing figures... and it seems like someone might have done just this.. I am going to go back through my ebay purchases when I get home form work and try and find if/when/who i purchased these off of...