GRENADE
WHEN: Your Shooting phase.
TARGET: One GRENADES unit from your army (excluding units that Advanced, Fell Back or have shot this turn) that is not within Engagement Range of one or more enemy units.
You might be using an old version of the stratagem, the current rules exclude units that fall back regardless if they have a rule that allows them to shoot after falling back from being targeted by the Grenades stratagem.
So no.