This is the header:
Received: from [192.168.0.2] (unverified [18.104.22.168])
by smail1.cableone.net [...]
No, that's not what it means at all, actually. Most major SMTP (the server that the sending client connects to to send the email to the recipient) have a function called Reverse DNS Lookup they use to verify the path of the email. In the case of this particular mail, the "unverified" part is in reference to the ip preceeding it, and the actual ip is appended after in brackets. If the SMTP (SurgeMail in this case) wouldn't have had this check, the header would have looked like this:
Received: from [192.168.0.2] by smail1.cableone.net
As mentioned, the SMTP is SurgeMail for this particular message, and here is a link
to the support mailinglist for SurgeMail and a message from someone who asks about this very feature, and here is a link
to the reply, where this process is explained: "unverified is not an error, it means that the server that received the message has not verified the name matches the ip address, which is normal since verifying it takes a lot of time and proves little".
The "name" in this case, is the name given by the sending client, which in this case is 192.168.0.2. The first links display a message from a client claiming to be "host2.clickndrop.com" which has the IP 22.214.171.124, but this hosts DNS isn't set up to reverse the IP either. It's worth noting that the majority of machines with domain names doesn't have Reverse DNS. Normal DNS checks the ip of a host name, while Reverse DNS checks the host of a IP.
Here is a link
to the SMTP server for Windows where their version of the same feature is outlined. "If the reverse DNS lookup is successful, the RECEIVED header will remain intact. If the verification is unsuccessful, "unverified" appears after the IP address in the RECEIVED header of the message."
Note the "after" part.