Does a Rule 12(b)(6)(6) motion that contradicts an assertion made in a motion is a presumption of truth?

^7. Although plaintiff's assertion is a factual one, under these circumstances it is not entitled to a presumption of truth (even if it had been made in the complaint rather than in the motion papers). That is because the Agreement has been incorporated by reference into the complaint, and it flatly contradicts the assertion. In a Rule 12(b)(6) motion, the court may reject allegations of the complaint that contradict matters "properly subject to judicial notice or by exhibit." Sprewell v. Golden State Warriors, 266 F.3d 979, 988, as amended on rehearing, 275 F.3d 1187 (9th Cir. 2001).