I was concerned with electrical not hydraulic systems. It is automatic for hydraulics so no training is required. That is why it was never taught except maybe in initial ground school once. It does not affect the electrical system.
From my memory over 10 years ago the 767 had a hydraulic driven generator that would be driven by the Hyd system. All my manuals drowned in Hurricane Wilma in 2005 so have no references to go to, only memory. If RAT would have taken care of total electrical failure I wouldn't have put my 'battery saving plan in my last resort checklist when I was current.