Yep, exactly. Outside North America, parts and service manuals generally go by vehicle serial number range and/or production date range. This method wasn't totally foreign to the US; Dodge trucks worked that way for quite awhile. They were registered by model year, of course, because that's how state registrars were set up. But the parts and service manuals up through sometime in the early-mid '70s were by serial number, not by model year.