[ x-post stripped ]
Yes, there is a X-Message-Info header inserted, by Microsoft's public
mailbox servers, when a message is received. They are, however,
considerably longer than thirty two characters in length.
The header commonly appeared in my local spam sample collection, from
2004, through about 2007. By that time, I changed my spam processing
and handling and examples become rare.
I think it's safe to assume that anything being delivered outside a
Microsoft mailbox, ie. hotmail.com, msn.net, outlook.com, which
includes an X-Message-Info header, should be taken as a positive spam
X-Message-Info: (A 32 character string)
|Location:||Huddersfield, West Yorkshire, UK|
|Nodes:||16 (1 / 15)|