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 :
Dual Shock 3 Silver PS3 - DiscoAzul.it
Sony Ps3 Dualshock Black 9174097 -best - | Acquisti Online su eBay
Sony DualShock 3 PS3 | Back Market
CONTROLLER PLAYSTATION PS3 ORIGINALI (usato garantito)(cavo incluso)