Pearl;

Just as you've stated, from the factory, in my experience, the trunk matched doors (typically a UN16 or later a UN18 keyway - 5 pin) and Ignition was either the Swedisch ASSA or German Nieman - 6 pin.

Patrick;

What replacements were later fitted, or what creative modification may have been made to allow for a single key, or MAYBE what was even fitted originally by the many facilities (Canada, Belgium, So. Africa and who knows where else) which did the final vehicle assembly, MAY explain some differences.

Cheers