In New Zealand it's a requirement to have 1 hour (not all in one lesson) of spin recovery training signed off in your logbook for the issue of a C category (Grade 3 to you guys in the West Island
) instructor rating. I don't know about the requirements in Oz.
The C172's I flew were all approved for spinning in the utility category.
For one instructor I trained we started out in a C172 but it was so useless at spinning we had to change to another type. From memory it needed pro spin aileron to stay in the spin as soon as the aileron was centralised the spin stopped.
Many C172's will enter the incipient spin with flap deployed, spinning is forbidden with flap deployed, though I suspect some do spin them with flap. In fact if I recall correctly Utility Category requires clean configuration, i.e. No flap.
While the C172 is approved for spinning, in my opinion it isn't a suitable aircraft to teach spin recovery training.
The C150/2 was a different kettle of fish. Used to enjoy spinning out of a steep turn in them, both over the top and underneath. A lot of fun and it was a very good way to teach the recovery process as the most likely time other than a botched stall recovery for a spin was in an out of balance steep turn.