Hi,
Can't see the images at work, but if it's a '79 vintage Brembo caliper your best bet is to google Guzzi or Ducati Bevel in the States.
It all depends if the caliper is a PO5, PO8 model (parts are easily available) or a PO9 model (parts are hard to come by). The new rebuild kits have Teflon coated pistons vs the old steel pistons, grease and the rubber seal.
HTH
Gerald