I think it depends on where the split is that you are talking about; if it is directly after you cross into Pandora at rope drop, then the River Journey folks are usually told to hang to the left, the FoP folks were told to hang to the right (as far as I've seen, others may have a different experience).
Or, are you talking right at the queue for FoP itself? There's one lane for FP's and one for Stand-by. If it is your fast pass return time, then you go in that queue and will scan your band as usual.
ETA: mesaboy is right in saying many mornings the rope drop procedures change depending on situation and CM. If you are getting conflicting info, that's hard, but it's not your fault!