In your preferred email program is the ability to check the raw header contents of the email.
There is a delivery date near the top at which it arrived at your mail server, then reading down through the header it will list a few other dates and times. Delivery-date:
The originating date and time is when it left PPP. Check this and confirm you are happy with the timing of the originating email.
It needs to have originated similar to - X-MimeOLE Date: Tue, 27 Oct 2009 ??:??:?? +1100
Be interesting to know what peoples ?? are ... and state of receiving email. I'm helping a friend out with his email tonight and will see what it says.