should node type be custom in node_example_install?

The node_type_set_defaults documentation says:

When populating a custom node type $info should have the 'custom' key set to 1.

However, in node_example.install, the array doesn't have a custom value set.

  $node_example = array(
    'type' => 'node_example',
    'name' => $t('Example Node'),
    'base' => 'node_content',
    'description' => $t('This is an example node type with a few fields.'),
    'body_label' => $t('Example Description')
  );

Not sure whether I am misreading the docs or if this is just a minor oversight.