Why "THE uprising" and not "A uprising"?
Surely, if Barabbas is the parody of the dangerous (as heretical) Christ of the Gnostics, then he has to be connected with the "robbers" in general, and so with the entire Zealot movement, so "the" uprising can only be a reference to the Great Revolt of 66-70 CE.
Hence, if the Gnostic Christ "Barabbas" is in prison with the robbers, the Jesus "called king of the Jews" is crucified with two robbers, but only in the latter case there is a fulfillment of old prophecies. So who invented the episode of three crucified men on the Golgotha had in mind also the scene of a Barabbas imprisoned with the robbers.