As far as I know (which is not very much...) no version of CHDK can save a RAW+EXIF meta data (or the extended shutter speed information that can be used with CHDK).
There are tools out there that will take the EXIF file information saved with the .JPG file and copy it over to the .CRW RAW file during the conversion process...
Some information here:
FAQ - CHDK Wiki-Bill