OK, as an experiment, I stored a time value as something other than midnight or 7 AM (which is the UTC equivalent of midnight). The value stored in Oracle is '9/2/2015 3:35:00 PM'. ArcGIS Server assumes that that value is UTC, and the value returned is 1441208100000. That's fine.
Back to ArcMap: I add the ArcGIS Server map service as a layer and identify the feature. Again, the value displays as '9/2/2015 3:35:00 PM'. It is not converted to local time, which would be 7 hours earlier. In Runtime, I query the ArcGIS Server map service, and the time populated in the feature object returned is once again the UTC time, not local time [but at least it's internally marked as UTC]. Only JavaScript automatically converts to local time, like it or not.
Once again, if there were a way to configure ArcGIS Desktop to work properly with UTC values, this would not be such a huge issue. At this point, however, changing our database dates does not seem viable.
