Nah I'm pretty sure it's all custom. The colours of the icons are a bit darker or different in coloration, but the shapes might be the same. Are you shure you checked the 0.4 version? Not all icons appeared in previous versions and even after installing 0.4 I had to boot to get everything.
This file contains CSS definitions for all the Maemo desktop theme colors and fonts. Theme Name : Digital Nature Installed in : @CSS_FULL_DIR@