I never encountered them outside about a 500m radius of the zoo, but yes - they were very common in the zoo itself. In fact, I was surprised to find they were gone when I first visited the zoo after moving back to Perth about 7 years ago. I'm fairly certain they were still around in 2007.
The squirrels and the butterfly house being missing were the main things I remember from my first visit with the kids in 2017.
People always used to say that Perth never changes, but it really changed a great deal in those 10 years.