Here's the read receipt I got:
Your message
To:
Michael.Campion@state.mn.us;
Mike.Parker@state.mn.us
Subject: Notification of Intent to Conceal Carry at MN Capital
Sent: Mon, 13 Apr 2009 17:42:59 -0500
was read on Tue, 14 Apr 2009 06:16:53 -0500
Final-Recipient: RFC822;
mparker@mail1.dps.state.mn.us
Disposition: automatic-action/MDN-sent-automatically; displayed
X-MSExch-Correlation-Key: Wa0SkIUz30i0TjVvZqiZqw==
Original-Message-ID: <49E3BFF3.2070109@bevcomm.net>
I would think this plus the original email would be enough.