recover mail not delivered to mailbox?

A client on one of my virtual servers reports that he hasn't received certain e-mails. In checking /var/log/maillog, I find two entries that reference the missing e-mails:

Sep 2 07:29:36 cor postfix/qmgr[3376]: E146FA869B: from=, size=2271, nrcpt=1 (queue active)
Sep 2 07:34:02 cor postfix/qmgr[3376]: 6D2F7A869B: from=, size=4575, nrcpt=1 (queue active)

I'm assuming (hoping?) that these e-mails are somewhere on the server - is there a way to retrieve them using the above information?

Status: 
Closed (fixed)