These were made through the beginning of the transition era, so the length of the board will be a good indicator of the year.
I see no wood that was added. It has a tapered t band stringer from what I can tell but there doesn’t appear to be any additional wood. Also has a pair of offset glue lines.
That blue circle in the deck is where the fin bolt went. Hansen had their own fin system for a few years and used a bolt through deck design. The fins were molded with threaded holes to accept the bolt.