Hi —,
I often use invisible sprites as spawn points, not sure if this is the method you are using?
If it is, perhaps you could add an instance variable to each spawn sprite. Then once a particular coin has been collected, update the instance var for its corresponding spawn point and save it. When you come to respawn a level, only spawn coins at spawn points where instance var is = ?.
Jeez, I've never used the word spawn so many times in a message ;)
Anyway, not sure if this will help, but it's one way you could do it!