Restored PlayStation 3 Dualshock Black Controller (Refurbished) - Walmart.com
Real or fake Dualshock 3? : r/PS3
Is this a real Dualshock 3 controller? Seller claimed to be genuine : r/PS3
10x Ways to spot Fake PS3 DualShock 3 Controller including Packaging (Before & After Buying) - YouTube
Official Original Playstation 3 Ps3 Dualshock 3 Wireless Controller NEW | eBay
How to Spot a Fake PS3 Controller Before Opening the Packaging - YouTube
How to Spot Fake PS3 Controllers, DualShock 3 - YouTube
I bought a sealed dualshock 3 and it's genuine (tested with MGS HD collection) so I figured maybe it can help you as a reference when looking for original ones online :
Sony PS3 DualShock 3 Wireless Controller - Electro Hive
Sony Dualshock 3 Wireless Controller for Ps3 Black