This is what threw me before mate, I always thought that a 3T-GTE flywheel was bigger than this and the clutch to suit this is 224/5mm.
I hate to say it, but I think you have been sold a 3T-C flywheel.
Going back to what Dom said above, stirred the memory a bit, and IIRC the early 1G flywheels had a 224mm clutch while the later (gen 3 1G-GTE's) use a 236mm clutch, and its this flywheel you need to mate up to your existing Hilux set-up.