A bit of info on works RN 500s, I worked on 1983 Models in 1984,
the Factory stopped Racing at the end of 1983 although they produced spare parts in 2 advance orders early and mid 1984,
they were single downtube frame with offset intake and exhaust, most 1983 bikes were air cooled, Harry Everts was allocated a couple of watercooled bikes, the bike featured for sale, unfortunatley has little in common with 1982 to 1984 works RN500s.