[unruhjonny]

It was probably changed AT the dealership.
I have understood that it was not uncommon for selling dealers to change wheels from one car to another in order to make a sale.

Your build sheet shows it invoiced for GM overseas so no dealer stateside would have had this car before it was shipped;
If you ordered PHS, and somehow came to the conclusion that it was ordered for a stateside dealer, or stateside alotment, then your guess wouldn't be a far stretch of the imagination - but becasue your built sheet makes an airtight argument for it never sitting stateside (other than awaiting shipment) then that kills your idea as to where or why the wheels were swapped.

I have understood that the Honeycomb wheels were a big deal in 1971 - so odds are the original purchaser either saw it set up that way by the dealer, or asked the dealer to change wheels with another car before he took ownership.

That spare is just one of the five original wheels that your car rolled off the assembly line with;
If your car was ordered with Honeycomb wheels it would not have a Rally II spare.