(a) An instrument may be antedated or postdated. The date stated determines the time of payment if the instrument is payable at a fixed period after the date. Except as provided in AS 45.04.401(c), an instrument payable on demand is not payable before the date of the instrument.
(b) If an instrument is undated, the date of the instrument is the date of the instrument's issue or, in the case of an unissued instrument, the date the instrument first comes into possession of a holder.