(2) Subject to subsection (3) of this section, if the incomplete instrument is an instrument under ORS 73.0104, it may be enforced according to its terms if it is not completed, or according to its terms as augmented by completion. If an incomplete instrument is not an instrument under ORS 73.0104, but, after completion, the requirements of ORS 73.0104 are met, the instrument may be enforced according to its terms as augmented by completion.
(3) If words or numbers are added to an incomplete instrument without authority of the signer, there is an alteration of the incomplete instrument under ORS 73.0407.
(4) The burden of establishing that words or numbers were added to an incomplete instrument without authority of the signer is on the person asserting the lack of authority. [1993 c.545 §18]