Deep voice, Adam's apple, big hands, big feet etc all the usual
Natural boobs are still not 100% because if they started hormone replacements quite young, they will develop small boobies. And most asian girls only have small ones anyway if they are natural.
I been told the best indicator is still the actual fanny - Apparently no matter how good the op, a fake fanny will feel very different from a real one. Its not just the fact that it will be bone dry but mainly it doesn't wrap the cock from all sides.
I have no direct expreience of this but just been told by another punter who is into TS. No ideas if he is talking bollocks or not.