Expecting a theatrical trailer to sound like the final version of a film soundtrack is an exercise in futility. It is highly unlikely the same sound effects would have been used, and extremely likely the trailer was not mixed by the same people.

Therefore, the existence of such differences proves nothing.

Also, Gary Rydstrom was the sound designer for the original mixes, not just the redone version.

I see no reason to doubt disclord's information that the early DVD used the CDS 5.1 master. Somebody should find a laserdisc PCM track of the Dolby Stereo version and see how that sounds—chances are it is pretty similar.