To be fair, I don't know the APQ/AEX in detail, but the majority of reasonably recent engines stress the head bolts. Some, like the Rover K series actually pretty much hold the whole engine together with them!
I'd be surprised to find that the engine in question was old-school enough that it didn't matter, but it could be the case. It should be noted that even if you *ARE* planning to *try* reusing the bolts, they need to be carefully checked against a specified permitted variance from original spec. If *any* are out-of-range of tolerance, the whole set needs replacing. This even applies if the bolts are not designed as stretch bolts. They *will* have stretched.
Personally, I'd change them out of hand if I was heaving the head off. Depending on why the head was coming off, I'd probably also want the head crack-testing and checking to see that it was still the right shape, too...
Why? Same reason I wouldn't be re-using bolts that held safety-critical steering or suspension components together that were likely to see cornering loads, except that in the case of the engine it's only the engine that would be dieing if the bolts failed.