And we can only speculate as an expat upgrade has never happened before .
Course they have, they have always upgraded FO's in accordance with their seniority, last group were from 747 Classic to Embraer, they even developed a program of right seat flying to get them proficient with the glass cockpit, some made, some didnt and returned to the Classic.
There are FO's on the A330 who have either undergone their upgrade evaluation or need to get their ATP written's done prior to the evaluation, so to say that it has never happened is unfair, BUT it has taken these guys 10 years for their seniority numbers to come up!