I don't see how you could have looked since you don't have the vB3 code but we only refer to $HTTP_POST_VARS when the server is running php < 4.1. You shouldn't base your assumptions on a test script that has to work on php 4.0.6 and greater.
PHP Code:
if (PHPVERSION < '4.1')
{
$_GET = &$HTTP_GET_VARS;
$_POST = &$HTTP_POST_VARS;
$_COOKIE = &$HTTP_COOKIE_VARS;
$_SERVER = &$HTTP_SERVER_VARS;
$_ENV = &$HTTP_ENV_VARS;
$_FILES = &$HTTP_POST_FILES;
}
As for using TRUE/FALSE or 0/1 - we are using true/false more but just switched over so you will see both instances for now.