The only T series motors sold in Australia were:
2T 1600cc motor in the TA22 Celica, circa 1972
2T 1600cc motor in the TA23 Celica, 1976
3T 1800cc motor in the TE72 T18-SE, 1979-1982 or whenever
If you find differences in the castings, then you may have a 2T Celica head. I don't think there is heaps of difference. I have both a 2T and a 3T head in the back shed, to give away.
Other differences could be due to random junk that has been imported over the years, such as the 12T and 13T very similar motors. T motors came in heaps of Japanese cars in the 70s- early 80s but we only saw a few of them.