No - the odds of The Gone Jackals doing the sequel are slim to none. This is partly because of what Keith and Rudy said in their interviews for The Kickstand (
http://hickstand.mixnmojo.com) ). Keith's is the only TGJ interview up at the moment.
Both stated that the deal with LucasArts for Full Throttle was a one-shot deal. Plus, if I am looking at it correctly, the Jackals disbanded (napster really hurt their cd sales) and Rudy & Keith now front a band called BoneDrivers. The Gone Jackals website is
http://www.blueblack.com) - you can find "Bone To Pick" (The Full Throttle "soundtrack") and "Blue Pyramid (their follow-up album) for sale on that site, plus news about Bondrivers, discography, etc.
Hope this helps