I've been reading through the second edition of Bauckham's Jesus and the Eyewitnesses. He has an extended chapter on the names of the Twelve, and I was struck by something in the lists as given in the Synoptic Gospels and Acts. But before I get to that, some initial observations. In each of these texts, there is a list of the Twelve. The lists are remarkably stable. Eleven out of twelve names recur in all four, vitiating greatly the argument that by the time the Gospels were written the number "twelve" was fixed while the exact names were highly fluid. Moreover, the one is divided between Mark/Matthew (which refer to Thaddeus) and Luke/Acts (which refer to Judas, son of James), and thus--given the common authorship of Luke and Acts--we actually have only one author varying from two. Add in the very cogent argument that Thaddeus and Judas are in fact the same man and you've got a remarkably stable list. The order varies, but even that is limited. As Bauckham notes, each list is divided into three groups of four, and each group has the same four names (with Judas of James taking the place of Thaddeus in the Luke-Acts lists). Moreover, each of the three groups is in each list headed by the same name. This reeks of intentional mnemonic devices, designed to greatly facilitate one's ability to remember the list.
What interests me more than all that however is the handling of the sons of Zebedee. In Matthew, Mark, and Luke, James, son of Zebedee, always comes before his brother, John. In Matthew and Mark, John is referred to as James' brother, and no familial relationship is mentioned at all in either Luke or Acts. It has been suggested to me in personal communication that this order might well reflect a reality that James was the elder brother, and that is altogether possible. Nonetheless, this is quite the interesting phenomenon, because John in fact is the one who was more prominent in the Christian tradition by at least the second century, if not earlier. All indications are that in short order there was more energy invested in remembering John than in remembering James. That is perhaps because James died in 41 or 42, during the Agrippan persecution (cf. Acts 12), whereas Paul would later describe John as one of the "pillars" in Jerusalem (cf. Gal. 2). John's connection with the Gospel of John--real or fictive--would no doubt have also contributed significantly to his prominence. Yet, Matthew and Mark explicitly refer to John not in his own right but by reference to his brother, while Luke refers to James before John.
But here's where it gets interesting. In the list in Acts, John is mentioned before James. Why does Luke present James first and John second in his gospel, but reverse that order in his Acts? One could say that he simply remembered differently when he was writing up his respective works, and that's probably quite likely. I don't imagine that this variant was particularly intentional, but that doesn't obviate the possibility that it is significant. Combined with another detail, I would suggest that Acts reflects the reality that by the time Luke was writing, John was more prominent in Christian consciousness than James. In Luke, the author follows his Markan (and I think likely, Matthean; I don't abide Q) source, and places James before John, but (unlike Mark or Matthew) does not mention their familial relationship. John now stands in his own right. In Acts, no longer with Matthean or Markan versions rumbling around in his head to the same extent, he more naturally places John before James, because John is more prominent in Christian historical consciousness.
Of course, such a reconstruction is more comprehensible on a lower chronology than a later one. If Mark wrote c. 40 and Matthew c. 50, as I would argue, then it makes sense that John has not yet eclipsed his brother. Circa 40, James either is still alive or only recently deceased. It is quite possible that for whatever reason--perhaps their relative ages, or their temperaments, or whatever--James tended to be more prominent in the early movement during that first decade. By c. 50, John might be coming more to prominence, but not so as to eclipse his brother's position in the tradition. But by c. 60, he's up the better part of twenty more years to make contributions to the movement than his brother ever did, and his prominence in Christian awareness exceeds that of James'. By contrast, there is no ready explanation for why James would be more prominent in c. 70 but John more prominent by c. 85 or even c. 125. What changed in that period to make John more prominent? One could argue that it was the production of the Gospel of John, but that then opens up the question of why that gospel was attributed to John. Given the tendency of the middle and especially the higher chronologies to suppose that the texts are pseudonymous, the inclination for such chronologies would naturally be towards supposing that John's prominence in the tradition led to the attribution rather than the other way round (there is of course the question of "Which John?" with regard to the gospel, but it does seem that at least in second-century consciousness John, son of Zebedee, was generally assumed to be the answer). For the middle and higher chronologies, the variants on this matter between the lists of the Twelve would probably have to be described as the result of mere randomness. Mere randomness is not implausible, but presents as somewhat less compelling than a cogent historical narrative can account for the precise features of the data in explicable human terms.