it is possible the car was originally sold in Japan? By law cars sold into Japan at that time had to have the mirrors viewable through the windshield.
"For a crash course in the history of rear-view mirrors in Japan, I contacted the Japan Automotive Manufacturers Association and spoke to Ryuji Osuga in the technical division. Osuga explained that fender mirrors were standard equipment on passenger cars in Japan until 1983, when the law was liberalized to allow for door mirrors as well. Door mirrors had become the norm in the Western market, and foreign car-makers argued that Japan’s refusal to recognize side-door mirrors amounted to a non-tariff trade barrier." The Japan Times
