What it appears they've done is to use Logic 7 processing to extract the 5.1 track from the DD 2.0 source. The sound quality is very similar to the DD 2.0 track, which is also included.
I can confirm that the codec is DD 5.1 and at the 448kbps rate (via PowerDVD on my computer).
The film looks fine on my PC (20" Dell LCD) but I'll spin it up when I get home. I did rent the original DVD many years back so I won't have the best memory of it, but the new transfer so far looks good to my eyes on my work monitor.