In episode 40, at 02:59 (time)

When kakashi just put a seal on sasuke and orochimaru came in. This are the exact quotes:

Kakashi: What do you want with Sasuke?
Orochimaru:You're lucky, since you got what you wanted already
You didint have that a long time ago
That... Sharingan in your left eye

now, I believe that Kakashi's eye is an implant? Like Orochimaru later says, that he wants one too. or am I wrong? No spoilers Plz!