I think it's different on different aircraft.
I've seen pics of VS upper class on the top deck aswell as in the nose. Although I've been on a VS B747-400 that had premium economy class in the nose and upperclass upstairs.
Lady Penelope and Tinker Belle both have Upper Class in the nose and the first three rows of the upper deck. The remaining 10 rows of the upper deck are Premium Economy seats. A curtain separates the two.