Doc-
The Alcan was built at the beginning of WWII and was completer in 1942.
FWIW and reference.
Except that completion didn't include actual pavement until much much later.
I guess there are different concepts of "complete". I haven't driven it in a few years, though I've been over it a bunch.
In some parts they should stay with chip-seal and avoid pavement. Gravel is even easier to run a grader blade over.