Search by Custom Field content OR post id via the WordPress Dashboard

I worked it out for myself – just add a second code snippet!

I got the following from How to search custom posts by ID in WordPress dashboard on Codexin

/**
 * Add search custom posts by their ID in WordPress dashboard
 *
 */
add_action( 'parse_request', 'cdxn_search_by_id' );
function cdxn_search_by_id( $wp ) {
    global $pagenow;

    if( !is_admin() && 'edit.php' != $pagenow && 'students' !== $_GET['post_type']) {
        return;
    }
        
    // If it's not a search return
    if( !isset( $wp->query_vars['s'] ) ) {
        return;
    }
        
    // Validate the numeric value
    $id = absint( substr( $wp->query_vars['s'], 0 ) );
    if( !$id ) {
        return; 
    }
        
    unset( $wp->query_vars['s'] );
    $wp->query_vars['p'] = $id;
}