Why do I have a dozen copies of certain preference file in my ~/Library/Preferences folder?
Yes these are temporary file created by the NSUserDefault class when storing new preferences. 

First, the temp file is created, then filled with the data and then the temp file replace the older one and gets deleted. 

For some reason the were not deleted. You can check but I'm sure .Globalpreferences.plist has a more recent modification date than .GlobalPreferences.plist.jFulwSB. If it's in fact so, you can delete them.