200th Birthday

The below items are commemorative of the (first recorded) discovery of Johnston Atoll, in 1796. 

Front features one of the atoll's many nesting seabirds... looks like a brown booby!

The T-Shirt would have been made (presumably in 1996) during the time of JACADS (Johnston Atoll Chemical Agent Disposal System) and within the last ten years of the island's occupation.

These two items were purchased separately, and only upon photographing them did I realise that the patch (below) has the date '76 although it should be '96 (1796 or 1996...) unless I am missing something as to why the below patch might have been made twenty years early.

The patch however shows a rocket launch from JI, which may be referring to the Thor-Delta being held there at the time, and the multiple launches and tests that took place on the island. This would suggest that the date is intended to be 1976 and that the patch is in fact made twenty years earlier than the t-shirt. Why might they be referencing a bicentennial of JA in 1976? 

Let me know below.