Well, it sounds like it was modern when it was found (1964) in most of the footnotes. But, yeah, it is sort of open to interpretation.
If it's some old lifeboat from the 19th century or something, that actually is more acceptable than a lifeboat from 1964.
I'm also wondering if there's some sort of circulation in the Indian Ocean. Like how shit thrown in the sea off the coast of Japan eventually circulates around to North America.
Alternatively, Reggie's explanation could be true.