I have long known that ships on the west coast or the Pacific were Fleet Post Office (FPO) San Francisco. Ships on the east coast, the Atlantic or the Mediterranean were FPO New York. This is a decoder for shore stations overseas.
My Midway shipmate, Phil Eakin, shared the following information with us from the Blue Jacket Manual. This is from WWII, but the idea of the FPO’s remain today.
Locations appeared as postal code abbreviations during World War II in order to keep unit locations classified.
Jones is located at the Naval Advanced Base at Noumea, New Caledonia.
*Number assigned but never activated.
From the webpage, so you can see the derivation for Noumea, New Caledonia:
131 SF Noumea, New Caledonia
132 SF Auckland, New Zealand
133 SF Wellington, New Zealand
134 SF Brisbane, Australia
135 SF Sydney, Australia