Blondie, good research. To me, from what I see, the wedding ring origin and use is very similar to that of many other things, like saying 'bless you', throwing rice, or ceratin holiday commemorations, that also may have pagan origin.
I do soemtimes speculate personally that there may be a somewhat ulterior motive involved here - if the WTS were to say, in effect, 'no rings' then I wonder if some betrayed spouse somewhere would hold them indirectly repsonsible a commited adultery. That's a big stretch, quite a reach, but who knows? I am just suspicious because they seem to single out wedding bands as okay while condemning so many other common practices, that, by the way, certainly do not make people think back to ancient pagan rituals. "Bless you" said these days, for example, does not carry the same meaning to the speaker or hearer as it did so long ago. Today, it's mainly just a way of being polite, from what I can tell.