Hmmm the guy that wrote that article even sounds like a professor...dry,boring and never reaching a point..I guess that's why his article is on zdnet and not a real website... Maybe he was the expert witness in the case of the 'Trojan Defense'

Anyways to answer the original question, yes it's routine to verify the data you are presenting in court is the exact same data that was on the original disk. That's what hashing is all about, a means of verification that a==b.
The trick is for the lawyers to be smart enough to trap the so called "expert". They try to trick the expert just like in any other court case..getting them to dispute their findings. Or they try to call in to account that the expert isn't such an expert afterall. They'll force the expert to explain how hashing works and call their methods in to question. And if the expert botches that part of the cross, then you can pretty much kiss the case goodbye. You don't have chain of custody? Kiss the case goodbye.

Timestamps are a nice way to correlate data, but at the same time..timestamps are so volatile. You can pre/postdate a file in a number of ways(man utime) and it's trivial. However there are ways to detect this..such as inode discrepancies..which is why you have to have a firm understanding of how the filesystem creates the files..and no it's not random.

The key is tying the person to the file(s)/activity at the time in question. If your findings and the lawyer can't do that then game over.