...iPhone os / ios : 4.0 ,4.0.1 .... Could I? As said above I have an iPhone 3G Says it has SHSH's on file for iPhone OS/IOS 4.0/4.0.1

Now I have an iPhone 4 which I accidentally updated to 4.0.2 and so I was wondering if I can use this shsh from my iPhone 3G so that I could downgrade my iPhone 4 back to 4.0.1