If you mean, is there provision in scripts to set where to install stuff, the answer is no, the target virtual drives are hardcoded, for simplicity.
But if you look at the sources of most scripts, the target is explicitly set in one place, and Diablo 3 script is no exception, see the PREFIX= line at the beginning of script:
http://www.playonlinux.com/en/app-1195-Diablo_III.html