Whilst op-ups may be common on Emirates on QANTAS they are rare. Even for top tier members the chance would be very low.
Points upgrades would be processed first. Op-ups will only be done if e.g. economy is oversold and not enough customers put in points upgrade requests to upgrade to premium cabin(s).
Great, thanks for your help. only a short flight so not sure I will bother as i'll probably only end up getting to premium then.