Okla. Stat. tit. 12A, § 12A-3-113: Date of Instrument

DATE OF INSTRUMENT

(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 date. Except as provided in subsection (c)

of Section 4-401 of this title, an instrument payable on demand is

not payable before the date of the instrument.

(b) If an instrument is undated, its date is the date of its

issue or, in the case of an unissued instrument, the date it first

comes into possession of a holder.