My guess is that Varese Sarabande did the re-release because they originally had and have maintained the rights to release that score.I wonder why Intrada didn't get the third one if they did the first two. It would have made sense for the entire trilogy to stay on one label. Of course, the score is the score so it's no big deal, but if I had been able to order both from Intrada I would've saved shipping.
Does the third one have the Doubleback song from the credits on it or not? If it's just the score, it may not, but I would like to get that song without having to buy it separately.
The ZZ Top song as heard in the credits is not on the Part III disc but the 'old timey' version that's played at the town dance in the movie is on there. Since the movies were released within six months of each other, it's odd to me that Varese released Part III but not Part II.