Is it possible (or sensible) to change a "prefab" in a script before passing it to instantiate?

For example, something like the following:

// assigned in the editor
var prefab : GameObject;

function Start() {
    prefab.GetComponent(FooComponent).ownerObject = this.gameObject;
}

function Foo() {
    var newObject : GameObject = Instantiate(prefab, Vector3.zero, Quaternion.identity);

    // now don't have to do this - a saving if instantiating many objects of this type
    //newObject.GetComponent(FooComponent).ownerObject = this.gameObject;
}

I tried this with Network.Instantiate, and it broke horribly and silently (at which I'm not surprised). Now I'm wondering if this would work with the standard Instantiate function?