Is 2 witness signature on a will as good a a notary

In California, a notary is NOT good on a will.  For a will to be valid, one of the requirements is that it be witnessed by at least 2 adults who have no interest in the estate.  So if the notary is also the second witness, then the notarization of the will is not needed but if it's done anyway it probably won't invalidate the will.