Also the AWM may be able to help. I would also suggest putting your query to their Research Centre.
If the query relates to a US military unit that was defending Australia in the NT or around Darwin, I suggest contacting the NT Library which has a large resource / list of Australian, Dutch, British, Canadian and US units stationed in the NT during WWII.
FYI, the same Japanese Convoy which attached Pearl Harbour, also attached Darwin on 19 February 1942, but with twice as many aircraft, and a large number of those killed where US sailors on the USS Peary.
Cheers