Yes. I know this. But at the same time without seeing the crack put on yourself or checking for the crack being installed to a folder somewhere you will have to wait for WGA to be updated to see if you still pass it. At this point in time the only thing you could do, is get something like Magic Jelly Bean and call Microsoft yourself and ask.
The only real test out there is WGA. Passing Microsoft's own test is the only way we can say yes or no the system is legit. There is no way we can tell you for sure that a crack was applied cause if that was the case the cracks would be no good since they would be detected so easily. the point behind them is to not be detected.
So if you pass WGA at this time there is nothing more that can be said or done. That is the ultimate test. At the point in time when WGA updates and you dont pass it at that time, then you will know for sure that a crack was applied and you can take action.
But till then there are no detection tools that i have seen other than WGA to test for the legitness of a Windows OS.