Universal did make a packaging change some time ago to differentiate between the two DTS pressings. All of the errored pressing have a black technical grid on the back. They later changed the packing on the corrected versions to have a red technical grid. So if you have a red technical grid on...
On U571, the DTS soundtrack's LFE is 4db higher than the LFE on the Dolby Digital soundtrack. No one really knows which version is actually correct. Many feel that the DTS is too high, since it hadn't been long since the screw up with JP DTS being 4db too low. But then again this time it could...
There is no way of knowing. The faulty pressings are still out there. I saw one Saturday at my local best buy. With this title, it is best to go somewhere where you can see what you are buying, and look for one with the red tech grid.