Well, there's been a lot of discussion about the object. as for apollo boosters, a reverse run of all the data from the orbits shows it may have left a geocentric orbit in 1971... timewise, that would narrow it down to only one possible S-IVb rocket... My confusion is that NASA and JPL have tried to use this same explanation for two other weird objects, 1991VG and 2000SG344.
Whatever, look for it on Sept 28th... it's going to be magnitude 42. Should be pretty easy to track, if you use JPL's data. Hopefully someone paints it with some radar and gets a good image.