Anything can be slipped through. My last KE55 had a 5K in it, and it passed rego because no one noticed.
Legally (in ACT) a 5K into ANY corolla needs to be engineered.
It doesn't matter what engine came out of what, and what it is in now, the rules are based on the increase in percentage from factory spec engine (in ACT) so if your car came with a 3K, you can only use an engine that is 15% bigger than 3K. If it's a 4K, 15% is JUST smaller than a 5K, so technically it is not legal.
I personally don't care, and have risked it many times, along with a SC'd 5K in a car that came with a 3K, so it just depends on how much you want to risk.