Not really. You have to have it signed, and notarized. Even then it can be contested by someone who feels they are' left out' or didn't get their share, or ( most likely) that someone else 'influenced' the person to sign a will to change the outcome.
An incomplete will will likely go to probate, to be decided by the courts.
A notary is simply an "official" witness. A will that has been witnessed is valid, although you may need to find the witnesses when it comes time to probate the will, which is why a notary is preferred.