After staring at those two pictures (for all together too long) the only "major" difference that I can see between the two is the differing lengths of fine and serrated edge. The top "version" has a 2/3 serrated and 1/3 fine edge, and the bottom "version" seems to have 2/3 fine and 1/3 serrated edge. All that I can think is that maybe the only "difference" in the Tiburons pictured are different model years, when Buck or the collaborator in the Tiburon increased or decreased the serrated edge.
But a Buck Representative is the only one that can clear this question up for certain.
GeoThorn