You are talking about the piece for air-shrouding? I don't think they sell those separately. Your best bet might be to goto a junkyard and pop them off injectors there. Then they might not even charge you for them.
You don't need them, the injectors work fine without the caps, spend 99 cents for the plastic, short single piece injector cup for the head or, you could just run with what you have. See if you even notice a difference. good luck