I'm trying to find information on if the IDispatch interface throws, specifically if IDispatch::GetTypeInfo() does. IIRC, IDispatch::Invoke() can, but I can't seem to find anything on the subject and the documentation here or here doesn't mention anything about this.
None of the standard COM interfaces will throw. COM was designed to be language agnostic, including languages that don't have exceptions.
It's entirely possible that the implementation of a COM object might throw, but that's up to the implementation of the object itself. Normally a COM object will indicate an error by returning an error code for its HRESULT.