I have both the original laserdisc THX-WOW, and the THX Ultimate Demo Disc. They are different. What most people are refering to as the VOBs are the 7 minute opening of the laserdisc that was "re-done" for the DVD (in 5.1 sound now for DVD) with all scenes from Lucas movies (SW, Indiana Jones, and Willow).

I don't know of anyone that has transfered the original laserdisc to DVD yet, but it is completely possible. The extras of both discs are completely different.

Here is two pictures of the covers (front a back)

Here are the links to the fullsize ones if you wanna try and read the backs:
Full Size Here
Full Size Here