there are few (if any) documented cases of "Thai Stick" being dipped in opium. For the most part, it's a rumor that went around because most thought marijuana couldn't be potent without an additive.

Thai stick is just good sticky bud (I'm not sure of the strain) wrapped around a stick and dried. If it does have opium on it, I'm pretty sure I don't want to smoke it, but have fun.