Found Amendment to Living Trust that was signed by both parents, that have now both passed. Yet was not Notorized, is it still valid in a Court of Law in California
A trust does not need notarization to be valid, if that is what you are asking.
Assuming that the trust was properly drafted and was signed/dated by your parents, the trust is valid. As Mr. Shen has said, in California, a trust does not need to be notarized in order to be valid.