Well the inclusion of a 3D-rendering of the throne indicates that they were at some point planning to produce the throne (and maybe still are?), but it's still concerning that it wasn't shown with Jabba himself at the convention and isn't in any of those unpainted test photos of Jabba above.
What really bothers me is that the original Kenner version of the armrest stand that the pipe/bowl fit on had two pegs on the bottom of it that would snap into the throne to hold the armrest in place. The giant sized armrest pictured with Jumbo Jabba at SDCC doesn't appear to have two pegs on the bottom since it lays flat on the surface of the table, similar to the modified one that Hasbro produced for its 2003 Ultra Jabba figure.
So that might indicate they've abandoned doing the throne due to the high production costs and will only give us what was shown at SDCC -- just Jabba and Crumb with a modified armrest with pipe/bowl.
I can't believe nobody bothered to ask GG reps at the booth or during their Q&A session about the lack of Jabba's throne. If they did, there's certainly been no report of it online.
And again, if there's no throne, then I'm very curious how they're going to portray this item's packaging. If its a faithful recreation of the Kenner box, then it'll have to include Jabba's throne in the photo as well as Jedi Luke and Squid Head. And people are going to wonder why we're not getting any of those.