Yes!
If you have one client configurated to read those old e-mails (let´s say you´re using M$ Outlook for this), you can configure IMAP access to your SME server and move/copy messages from origin to SME server. That could be a little slow for a BIG amount... but it´s garanteeded.
If you have another situation, please tell us wich one and we´ll try to help you.
Good luck
Jáder