Many popular naked bikes are basically sportbikes with their bodywork removed. Why not? It's a good formula. It gives you all the performance of the fully-faired model without the extra weight. Manufacturers can get two distinct models from a single platform at little additional expense.
Not KTM. They designed the 1290 Super Duke R from the ground up to be a naked bike. The Super Duke GT and Super Adventure do share its 180-horsepower, 1,301cc V-twin engine, but their trellis frame designs are obviously different when you look at them from the side. The 1290 Super Duke R remains unique.