From its conceptual beginnings in the mind of Abe Silverstein to Apollo 17's final splashdown, the Apollo mission and its mission schedule was nominally to do one thing and one thing only: put men on the Moon and bring them home before 1970. All of the missions prior to Apollo 11 were subordinated to a plan involving numerous milestones required to accomplish that objective. Each mission (even as the schedule was reconfigured for Apollo 8's unplanned lunar journey) was meant to be a new piece in the puzzle - a working Saturn V, a working CSM, a working LM, a lunar orbit, a rendezvous between the CM and LM, and a demonstration of a nominal landing. The missions that came after 11 were then to take advantage of the scientific opportunities that the landings could yield, and they anticipated a much longer and detailed schedule before the program was cut.
For this reason, I think even those flights that used Apollo hardware couldn't be considered true Apollo missions, as Apollo was an operation with distinct objectives where the goal of the mission was just as much a part of the paradigm as the hardware itself.