They're not open-source hardware in that sense. What they publish is a 19-page pdf of schematics of how the components are put together [1] -- and even that has redactions due to NDAs (like page 14 -- the say they have a "super NDA" with the GSM chip provider that bans them from even publishing the datasheet!) The components themselves (like the Samsung SoC and the GSM chip) are completely closed.
"Open" in that they show you how they put together the black boxes. "Closed" because it's all made up of black boxes.
