It is a common problem. "origin" is more "spiritual origin" or "country where it was originally designed" than build location.
I would list the Hino Renault as origin=France (as the car was designed there) but "made for=japan", as some details change.
For the other one, if it is the same car (i.e. same body style, etc.) simply built in Japan, I would maybe keep the original country flag (UK/US).
I notice that all except 2 Hino Renault are currently listed as origin=Japan, though.

I wonder where is the origin
*example
http://www.imcdb.org/vehicle_92303-Hino-Renault-PA58-1958.html?PHPSESSID=2668f7b5e176eb62060e1aa2c61a6c75
http://www.imcdb.org/vehicle_92298-Nissan-Austin-A50-Cambridge-1956.html?PHPSESSID=2668f7b5e176eb62060e1aa2c61a6c75

These Renault, Austin, Hillman, Jeep and Henry J(Kaiser) was constructed under licence in Japan.
Some modifications are applied, but actually based on French, UK and US cars.