Need help regarding wrong info on car reg card

The "L" in the first position was, as this chart shows, used to designate 1966 Valiants in Canada. It was also used to designate Darts in the USA. This what McGee sent you applies to Canadian-market cars, which in 1966 was a subset (and not the totality) of Canadian-built cars. It would be an error to apply this information directly to your car and assume it means your car is a Valiant. It is possible Canadian-type '66 Valiants (i.e., 111"-wheelbase Darts badged up as Valiants) were exported to some markets. It is definitely the case that 1966 Darts were exported to some markets. Kevin McCabe probably has more definitive knowledge, but I think your car has always been a Dodge Dart, never a Valiant, and your VIN would decode this way:

L: Dart
H: High trim line (270 model)
27: Convertible
A: 170 cubic inch 6-cylinder engine
6: 1966 model year
9: Built at Windsor, Ontario, Canada