There are NO rebuild kits made for the brake nor clutch master cylinders. New complete brake assemblies are sold by the vendors, but the cost may approach $500 plus labor. Its the same unit as is found in the 308-328 series Ferrari. The master cylinder alone is not available. Your only other choice is to remove the master & send it to a shop that shrinks brass or ss sleeves into the OEM casting. White Post Engineering (advertises in Hemmings) does this. Expect to pay maybe $150 for the service, but the internals are bored for a common repair-kit size so the thing is then rebuildable. This usuaoly happens when brake of clutch hyraulic fliud is no changed yearly, Water is condensed out of the atmosphere into the fluid and rusts the cast iron bores. Attempting to drive the car this way loads the gear synchronizers in the ZF, wearing them. A ZF overhaul is around $1500- up.
