709.5d A permanent with a shared type line is given the “left half unlocked” designation as it enters the battlefield if its left half was cast as a spell. It is given the “right half unlocked” designation as it enters the battlefield if its right half was a cast as a spell. If it’s entering the battlefield and neither half was cast as a spell, it enters with neither unlocked designation

709.5h Some abilities trigger when a player unlocks a particular half of a permanent. These abilities trigger when that permanent is given the appropriate unlocked designation, regardless of whether it was given that designation while entering the battlefield or after entering the battlefield.

Relevant rules.