我找到了这个有效的代码。

参考号：https://gist.github.com/trinitybranding/72066ca34584535dccbe3290dee02791

我重命名了原始函数名。

function __hasMetabox( $meta_box_id, $post_type = false ){
  global $wp_meta_boxes, $grist_meta_box_found;
    $grist_meta_box_found = false; // assume not found by default
    // if meta boxes are not yet set up, let\'s issue an error
    if( empty( $wp_meta_boxes ) or ! is_array( $wp_meta_boxes ) )
        return new WP_Error( \'missing-meta-boxes\', \'global $wp_meta_boxes is not the expected array\' );
    // should we only look at meta boxes for a specific post type?
    if ( $post_type )
        $meta_boxes = $wp_meta_boxes[ $post_type ];
    else
        $meta_boxes = $wp_meta_boxes;
    // step through each meta box registration and check if the supplied id exists
    array_walk_recursive( $meta_boxes, function( $value, $key, $meta ){
        global $grist_meta_box_found;
        if ( $key === \'id\' and strtolower( $value ) === strtolower( $meta )  )
            $grist_meta_box_found = true;
    }, $meta_box_id );
    $return = $grist_meta_box_found; // temp store the return value
    unset( $grist_meta_box_found );  // remove var from from global space
    return $return;
}

add_action(\'add_meta_boxes\', function() {
  global $wp_meta_boxes, $post;
  if (__hasMetabox(\'submitdiv\', $post->post_type))
  $wp_meta_boxes[$post->post_type][\'side\'][\'core\'][\'submitdiv\'][\'title\'] = \'Amazing!!!\';
});