To add to the problem of identifying these bikes, there were MANY variations according to the country into which they were imported. Additionally, over the years, people swap and change parts including side-panels, tanks, forks, etc, etc.
So in answer to your question, it's a K2-K7
Yeah, seems to be quite a variation of them, depending on where they were for.
Myself, I've got one that by features, it's a K1, but by serial numbers, it's a K2?
Last comment I had about THAT one, was it might have been for Canada and someone brought it down here.