Is a prior conviction for possession of contraband with the intent to distribute a specific intent offense relevant to the material element of a conspiracy?

To knowingly and intentionally possess contraband with the intent to distribute is a specific intent offense. See 21 U.S.C. 841(a)(1). As we held in Arambula-Ruiz, defendant's prior conviction for possession of contraband with the intent to distribute is relevant to a material element of conspiracy to possess contraband with the intent to distribute and attempted possession of contraband with the intent to distribute, "because it tends to show knowledge." Arambula-Ruiz, 987 F.2d at 603; see United States v. Schmidt, 947 F.2d 362, 367 (9th Cir.1991) (knowledge of the objective of the conspiracy is an material element of any conspiracy conviction).