rcp_metabox_post_types

By default, the "restrict this content" meta box is added to all public post types. There may be some instances where you want to add the meta box to another post type, and this filter makes it very simple. All you have to do is add your post type to the array, like so:

function ag_rcp_metabox_post_types( $post_types ) {
    $post_types[] = 'post_type_name';

    return $post_types;
}

add_filter( 'rcp_metabox_post_types', 'ag_rcp_metabox_post_types' );