Um...
The sound difference between the 2004 and 2007 releases of the scores is inconsequential. The errors are still present, and the only major difference is the omission of the GREAT liner notes by Matessino... so really, I'd hang on to the 2004 release and not worry about getting the sony one until they fix it.
I wonder who I could contact at sony though. If I could find someone to contact there, I would...
EDIT:
I think just the artwork is duplicated, not the release.
And as for hidden, yes. If you listen to "Corbon Freeze" there is a segment after the carbon freeze Vader's theme, and before the Han and Leia love theme. This 30 second piece was the original music that was composed for when Han is pulled out of the tank and layed down on the ground, in place of the Han and Leia love theme... It was placed before the film alternate, but no mention of its inclusion is made.
from 2:39 to 3:20