How to give a gameobject an audio source through code?

I am playing around with the Leap Motion unity sample.

In it, game objects are created in a main script, as follows:
GameObject finger = Instantiate(m_FingerTemplate) as GameObject;

Later on a script is added to what looks like a subcomponent:
fingerTip.AddComponent(typeof(LeapFingerCollisionDispatcher));

How do I add an audio source, so that in LeapFingerCollisionDispatcher, I can call audio.Play() when a collision happens?

Because I create these objects in code, I don’t see how I can attach an audio source them outside of code. I think the solution must be to attach an audio source to the main script, then addComponent, but all the examples I’ve found don’t work…

Because I create these objects in code, I don’t see how I can attach an audio source them outside of code

Do you know that you can attached the audio component to the prefab m_FingerTemplate is referring to?