Genesis - Show Updated when post has been modified.

<?php

add_filter( 'genesis_post_info', 'dspip_post_info', 20 );
function dspip_post_info( $post_info ) {
    $diff = '';
    // If the post was modified after the publishing date then show the modified date.
    if (get_the_modified_time( 'Ymd' ) > get_the_time( 'Ymd' ) ) {
        return $diff .'Published: [post_date] (Updated: [post_modified_date])';
    }
    else {
        return $diff .'Published: [post_date]';
    }
}