Many times I have needed to get a copy of the dll that is in the GAC for a webpart.
I have been trying the different methods to get to the dll without the possibility of moving the reference to the GAC entirely (which you can do with the xcopy command! :-/ )
Here is a method I like:
To view the physical file structure of the GAC, add a DWORD value named ‘DisableCacheViewer’ to the registry key HKLM\Software\Microsoft\Fusion and set it to a non-zero value.
Works like a charm!