LiteStep modules are not always backwards compatible, so even if you have a newer version, the theme may not work with it. So the modules are all tagged with the version, and the theme is given the exact version that it was written for.

Now, the installer is a little old now, so it doesn't have the latest modules with it. Also, there is no way to update to the latest modules (partly for the reason above), so you'll never automatically get the latest versions, even right after install. Unless you're experiencing a bug it usually doesn't matter, and when it does you usually just have to change one line in a text file and recycle.