Selectable Gizmo With [DrawGizmo] as opposed to OnDrawGizmos

Questions & Answers
1

Is it possible to make a gizmo drawn through a function with the [DrawGizmo] Attribute (documented here) selectable in the same way a gizmo drawn through MonoBehaviour.OnDrawGizmos is selectable?
I only ask because, while functionally identical, I really like having my Editor and Game code completely separate, and this is one of the things preventing me from doing that.

2

Make sure to include GizmoType.Pickable.

[DrawGizmo(GizmoType.InSelectionHierarchy |
  GizmoType.NotInSelectionHierarchy | 
  GizmoType.Pickable)]
            static void DrawWhateverGizmos(MapInstaller scr, GizmoType gizmoType)

This seems to make all the gizmos drawn pick the game object.