If this is something you need to do for an array of events, then yea, you should probably try streamstats.
If just one, then you can try something like this: since you know the timestamp of the latest event, search for _timestamp < latest_event_timestamp and get the latest() out of the result set.
https://answers.splunk.com/answers/149904/find-earliest-and-latest-event-per-day-for-a-time-range.html
http://docs.splunk.com/Documentation/Splunk/6.1/SearchReference/Commonstatsfunctions
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