Yep, that is correct. Aristotle's works were divided into the "exoteric" texts that were published and distributed by the Lyceum - it is these that are referred to by Cicero and many other famous commentators. All of them have been lost since Classical times.
What has survived are the "esoteric" writings that were basically lecture notes or rough drafts that were never designed or refined for a general audience. I don't recall the precise details of the story, but I believe that an editor at the Lyceum (perhaps Andronicus of Rhodes) had hidden away a cache of these works and they were rediscovered in the late Roman Empire. Somehow they ended up in the hands of Arab scholars who translated them so that they were reintroduced to the West in the Reconquista of Spain from the captured libraries of the Moors.
It would be a most excellent triumph to reclaim the exoteric works, not only of Aristotle but also of the other famous scholars of the Lyceum (nearly all survive only in fragments, if at all).