Uh, I think it may be a 1977. I had a R75/7 from 1977 and it looked very much like this one. Had an S faring and Luftmeister on mine.
Pastor, Church of the Horizontally Opposed Air Cooled Twin
'66 BMW R60/2, '83 BMW R100RS,
'81 BMW R100RS "Das Beast", '77 Honda XL125