Hi,
You could use name conventions, go trhough each items, and compare names with a reference, Else ask the instance itself, using a special Fsm on the prefab that holds a reference to the prefab, for example a string or an int. Using the action "Get Fsm int", you can query an expected Fsm by name and an expected var by name too, it's VERY, VERY powerful as if it's not there it will not create any errors.
Bye,
Jean