Series V no. 622 was built in December 1965, so before the official date of the memo, but taking into account shipping to the USA and then to the dealer would quite likely not have been sold until after February 1966. Perhaps unsold cars in the "pipeline" had the Pentastars added at the dealers.
During the '60s and '70s, the British car worker unions usually put the self interest of their members ahead of the long term survival of the industry, but I'm not sure the American unions were much better. As I have heard it, union negotiated featherbedding of employment benefits contributed to the profitability issues of Ford/GM/Chrysler, once foreign competition made serious inroads into the USA car market.
That being said, a prolonged strike at Rootes' British Light Steel Pressings plant in Acton, London in 1960-1 which supplied body panels for most of the car range including the Alpine, seriously affected profitability at a crucial time. Another big cost was the opening in 1962 of the new plant in Scotland to build the Hillman Imp, which was forced on Rootes by British Government policy directing industrial investment to areas of high unemployment.
The Imp was unreliable and never sold in sufficient numbers to rival the Mini; the workers were militant ex-dockers and -shipyard workers who were inexperienced at building cars and the location remote from Coventry created additional costs and management problems. The death of Lord Rootes and loss of management dynamism; competition from Ford and Austin/Morris with more modern designs and the perennial lack of finance that Rootes always had for developing new models all contributed to driving the company into the arms of Chrysler.
Having got it, Chrysler then mismanaged the company for years, losing squillions until selling it for £1 to Peugeot.
Steve