FWIW Maastricht UAC, being the main customer for IANS in Luxembourg has been doing it this way for years.
After completing the initial training in Luxembourg, Maastricht specific training continues at the UAC, initially in the classroom, later in the simulator with coaching provided by controllers not instructors, terminating in the Ops. Room itself, so no, they wouldn't be plugging in with no previous R/T experience.
Furthermore, as they are actually at the unit, integration becomes easier. if they should find themselves with nothing to do they can normally observe on the sectors where they will be training. An extra benefit is that as they are already living in the area the cultural shock for many of moving to a foreign country is reduced and is not so much of a factor when they eventually enter the Ops. Room.