WindSheer,
Since you were "sitting" on the right wing, you were throwing off the balance of the aircraft in the roll axis, so no "up"aileron on the right wing would be needed to roll back to the right

. I have to guess the FBW computer was adding some crazy aileron differential to counteract the SLF on the right wing

In all seriousness, I have no clue

. But inquiring minds would like to know.
My limited knowledge of aeronautics tells me you would have adverse yaw if only the aileron on the low wing were deflected downward to roll back to level, but then I don't know if that applies to swept wing jet transports.
latetonite,
I don't quite see how reversed rigged ailerons would result in WindSheers observations. Only the PF would be painfully aware the ailerons were reversed.
I've been involved in R/C flying for 25 years, so I've seen all too many cases of reversed controls being discovered a moment after rotation. They rarely end well, but alt least only someones pride is dinged.
Pete