As far as I know that is an aftermarket bracket for the hydraulic couplers so they shouldnt be that hard to find. It looks like a Pioneer or Safeway brand. I believe the G1000 models were the first MMs to use the fixed brackets as those. The original MM ones for the other models before 1967, were a single flat iron with an end bracket for swivel purposes, and a separate clamp for each hose. Here is a parts listing picture and one of the reproduction brackets for them that I make.