I have taken the time to research this on the Japanese side, trawling through numerous Japanese market factory parts manuals for Nissan models made during the 1960s and early 70s period. I found some pointers. Dates quoted are the dates for the publication of the parts manual concerned: *Model 31 Nissan Cedric - 1963 - Both Zinc and Cadmium protective coatings applied to fasteners/components. *Model 310 Nissan Cedric - 1964 - Both Zinc and Cadmium protective coatings applied. *Model 410 Bluebird - 1964 - Both Zinc and Cadmium applied. Then, *B10 Sunny - 1966 - Zinc. *510 Bluebird - 1967 - Zinc. *T44 Nissan Miler (ex-Prince) - 1968 - Zinc. *T65 Nissan Clipper (ex Prince) - 1968 - Zinc. *Model 60 Nissan Patrol - 1968 - Zinc. *521 Pickup - 1968 - Zinc. *C30 Nissan Laurel - 1968 - Zinc. *A30 Nissan Gloria (ex Prince) - 1968 - Zinc. *SR311 Fairlady - 1968 - Zinc. *130 Nissan Cedric - 1969 - Zinc. *C10 Skyline - 1969 - Zinc. *C20 Vanette - 1970 - Zinc. *GC10 Skyline - 1971 - Zinc. *A-321 Cabstar - 1971 - Zinc. ...so, judging from the above, it seems likely that Nissan's use of Cadmium for protective coatings was discontinued around 1965. I also searched factory parts manuals of Prince Motor Co products (Prince were forcibly merged with Nissan in 1966) but they carry no data on protective coatings for their parts. Your move.