RP07
3.10 Crew Control may request a crew member to perform a duty on a GDO.
3.11 GDO Callout Compensation will be paid for working voluntarily on a GDO resulting from agreement to a Request from Crew Control, excluding:
B. Changes to Rosters to facilitate training prior to passing final Line Check of syllabus training (e.g. induction, conversion, upgrade etc).
You can only ever be requested to work on a G day. Getting rostered for non training duties is most definitely voluntary and will get callout compensation.