How to know if rotation is complete

I’m trying to run an auto shooting script once lockedTarget is true after the turret has completed it’s rotation and is looking towards the enemy target.

public class LookAtEnemy : MonoBehaviour
{
    // The enemy target.
    [ReadOnly] public GameObject enemyTarget;

    // The turret that will rotate and point towards an enemy target.
    public Transform turretTransform;
    // Smoothly rotate the turret towards the enemy target.
    public float rotateSpeed = 6f;
    // After smoothly rotating, is the turret pointing towards the enemy target now?
    [ReadOnly] public bool lockedTarget;

    private void FixedUpdate()
    {
        // Get an enemy target.
        enemyTarget = CommonMethods.FindClosestTargetTag(transform, "Enemy", false);

        // Rotate Lil John (turret) to point towards the enemy.
        if (turretTransform != null)
        {
            // Direction of the enemy target normalized.
            Vector3 directionToTargetNormalized = (enemyTarget.transform.position - turretTransform.position).normalized;
            // Desired rotation to rotate towards so that the turret is facing the enemy target.
            Vector3 desiredRotation = Vector3.RotateTowards(turretTransform.forward, directionToTargetNormalized, rotateSpeed * Time.fixedDeltaTime, 0f);
            // Make sure it does not rotate up/down.
            desiredRotation.y = 0f;
            // Now rotate Lil John!~
            turretTransform.rotation = (Quaternion.LookRotation(desiredRotation));
        }
    }
}

Can the turret targets move? If so, you don’t need to stop it, just clamp the rotation if it close enough and rotate it constantly towards current target