Enque script based on url paramater

There are a couple of ways to do this. The easiest way is to use $_GET:

if ( ( $hook == 'post-new.php' || $hook == 'post.php' ) && $_GET['action'] == 'edit' ) {
    // Enqueue your scripts here
}

You can also use the get_current_screen(); function instead of using a global variable.