What is meant by "RAW" firmware?
RAW is just the archive format used by the Asus flasher (as opposed to ZIP, EXE, IMG, KDZ, etc.). If you're using the Asus flash tool (AFT) and you downloaded a .raw file, you should be all set. AFT does not support other formats.

If you want to install the stock firmware as it comes from the official source (Asus website), then you wouldn't use AFT. The exact procedure you would use varies depending on what you've got installed now and if it will boot.