do I really need the auto trans pilot bushing?

[racemydatsun]

as title states, do i really need it? i am helping my bro put a motor into his girlfriends car(automatic transmission) my brother and myself got a motor from a friend that had a single cam ka laying around in his garage and his car was a 5 speed. We are putting the motor into a car that has a auto trans and cant find the auto trans pilot bushing anywhere?!?! we even called nissan and the parts guy over there is dumb as $hit and doesnt even know what a pilot bushing is.......long story short i am wondering if it is totally necessary to use this as the pilot shaft on the trans already slides into the converter

PLEASE HELP! Thanks in advance