Terms with respect to which the confirmatory memoranda of the parties agree or that are otherwise set forth in a record intended by the parties as a final expression of their agreement with respect to the terms included in it shall not be contradicted by evidence of any prior agreement or of a contemporaneous oral agreement but may be explained or supplemented by the following:
(1) By course of dealing or usage of trade (G.S. 25-1-205) or by course of performance (G.S. 25-2-208).
(2) By evidence of consistent additional terms unless the court finds the record to have been intended also as a complete and exclusive statement of the terms of the agreement.