There was an exception made early last decade for a bunch of experienced ex Ansett 737 pilots who were fast-tracked to 737 F/O outside of seniority.
Just to clear that statement up, they were all on a Forstaff contract and had to do the QF testing if they wanted a permanent position. They were then started at the bottom of the seniority list once the contract expired, like any other new starter and had to take up S/O positions.