Just decided to take a look at wp-mail.php
line #130
$post_date = gmdate('Y-m-d H:i:s', $ddate_U + $time_difference);
change the + sign to a – sign and the time stamps seem to come out correct.
Caveat though. I’m not a programmer and don’t know PHP. Don’t know if this will mess up anything else. Someone should verify. As far as I can tell, my install is working OK and the time stamps are correct.