You know those guitars are, like... double guitars? Yes, it is indeed one of those double guitars, whipped out by Tad Kubler for the mid-section of the set.
This is probably as good a time as any to point out just how bloody dark it was onstage during the show. I'd only seen one Stagedoor show before, but it was plenty well lit. This time out they had two small rigs onstage, pointing at nothing in particular, and that was it. It's kind of unfortunate, since Craig Finn is such an expressive guy when he's performing, that most of the room probably couldn't see much if any detail of what was going on.