Trying running a search on the PST file without any criteria and have a look at the Create/Modified columns. Those are the dates that you can filter on.
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There are many different date values in a PST email message, they are mapped to the Modified Date and Created Date values in the following order.
Modified Date: Usually maps to the last modification time for the message. If not available it maps to the Message delivery time and if that's not available the Message submit time.
Created Date: Usually maps to the Message submit time. If that's not available it maps to the Message delivery time and if that's not available the Message create time.