The patch alters multiple files, not just the exe. The exe is the most important, of course, and you probably don't need to backup the other files, but I can't say for sure. I have put the 3.06 files which are being updated in 3.08 for Windows here:
http://www.mediafire.com/?edgtzyyfyon
Just overwrite the 3.08 files with these and you have 3.06 back.