Was there any history of American aluminum/rivets being used in British aircraft, some RAF planes were produced in Canada during the war.
I don't know. What British aircraft were serving in the Pacific anywhere near Gardner Island?
The Empire Air Mail Programme
"1938 saw the schedules of the Empire routes being accelerated, and air mail figures for the first quarter gave an idea of how well the Empire Air Mail Programme was working. In three months over 100 tons of mail had been flown on the Africa route and the same volume on the India route. This service was given a great amount of praise from the United States where only 2 tons of air mail was carried per week in 1937.
On the 28th July Australia, New Zealand, Tasmania, Papua, Fiji, Norfolk Island, Lord Howe Island, Nauru, The Mandated Territory of Western Samoa and the Territories under the Jurisdiction of the High Commissioner for the Western Pacific were brought into the Programme."
The first mail left Southampton in Imperial Airways C Class flying boat G-AEUA Calypso.
None were lost so no chance of 2-2-V-1 being related