Yes, but I use mine as surrounds. The RF-62II are a better speaker for sure, but if space is limited (or funds) than you shouldn't have a problem using the bookshelf as mains. I'm guessing you are thinking about 3 RB-62II's across the front? Since you ask if they sell singles.One big plus about the RB-61II is it is front ported which helps even more with space issues. The RB-51's are rear ported.