Questions about a Hitachi EX-58mu

Just bough a dead EX-58mu Previous owner broke the main valve bank. All 8 of the little spool valve spring tower caps on the side sheared off, so I'll be buying parts in the future. Local Hitachi dealer is saying that they are 3-2 months out and a custom made to order part. Since this isn't a common machine, being grey market, I need to find a North American market equivalent. Does anyone know if models like a ex50 or ex60 would share the same parts? Need rear engine body panels too. I doubt that Hitachi would make a 1-off machine with unique parts and not share them in other models.