No sorting for custom post type

The theme I’m using has a built in slider and the option to sort slider options is not present. This is the code in the custom_post.php file. Is something missing here that would cause the post-types-order plugin from working? I’m not sure the developer adhered to whatever the codex defines as a valid custom post type?

<?php
// ==================================================================
// Post type - Slider
// ==================================================================
function post_type_slider() {
register_post_type('sliders',
  array(
  'label'               => 'Slider',
  'singular'            => 'Slider',
  'description'         => 'Slider content',
  'public'              => true,
  'capability_type'     => 'page',
  'exclude_from_search' => true,
  'hierarchical'        => true,
  'query_var'           => true,
  'menu_position'       => 5,
  'supports'            => array(
    'title',
    'thumbnail',
    'page-attributes',
  ),
  'rewrite'             => true,
  ));
  flush_rewrite_rules();
}

add_action('init', 'post_type_slider');

Thanks

http://ww.wp.xz.cn/plugins/post-types-order/