Some but not others; as for the latter I can provide one pseudo-measurement. When the Borders chain was shutting down, I went to the closest store (Bowie, MD) at a point when most of the books were gone and they were selling the fixtures (shelving etc.). The travel section, for example, still consisted of a few books, but mostly empty space. But there was a rack by the register that was still filled with marked-down copies of Going Rogue.
