I've noticed that within Notes (8.5.2, basic client, standard client and iNotes) the date/time displayed on the eMail envelope AND the date/time on the message header is the same and appearently that time that Domino received the message.
When using BES, the message forwarded to the BlackBerry by Domino/BES has the RECEIVED date/time on the envelope and the SENT date/time displayed in the message.
In the basic/standard client with properties the sent time is viewable in one of the "Received" tags.
Having the sent time easily viewable is helpful, especially if your trying to trouble-shoot a problem.
Is this a configuration feature? Is it selectable in the client or in Domino?