This Jabba will obviously be from ROTJ, as that's the version that the fans and collectors have been clamoring for for years now! Plus, it was stated in the Comic Con news that it will be included in the Jabba's Palace themed wave, which is not attributable to the ANH version.
I'm sure Hasbro's going to go all out on this one, due to making the fans wait for it for so long. Expect the dais, frog bowl, pipe, and probably a Slave Leia or Oola to keep Jabba company! Can't wait for Insider #71 to find out! Unfortunately, it sounds like we'll be waiting until March of next year to finally get our hands on one though. Hopefully it's worth the aggravatingly long wait! But the bottom line is that it's finally coming for sure, so I'm one happy collector!