What is the likihood of finding replacement parts for an old Kohler single lever bath faucet? The owner said that it is original to the house which was built in 1958. I looked for a model # but all that was visible on the cover plate is “Kohler Neideken Patd.” I hesitate to start removing the cartridge (or whatever is within) until I have some assurance that repair parts are still available, especially as the faucet is just barely dripping.