Re: appending to Message-Id: line after ">"

| They must be in parentheses.  The 'phrase' that is allowed before the
| angle bracket as part of an actual address in a sender or recipient
| header field is not allowed in the context of a message-id.

Thank you, Philip.  I had tried it earlier with raw open text and had had no
problems, but maybe I just ran into tolerate mail transports.