Is the admission of a prior criminal conviction relevant to the evidence used to prove that he had knowledge of explosive devices?

Manning challenges the admission of his prior 1972 conviction, which was used to show that he had knowledge of explosive devices. Federal Rule of Evidence 404(b) allows evidence of "other crimes" to establish "motive, opportunity, intent, preparation, plan, knowledge, identity, or absence of mistake or accident." Rule 404(b) evidence must satisfy four requirements: (1) it must prove a material element of the offense for which the defendant is charged; (2) in certain cases the prior conduct must be similar to the charged conduct; (3) proof of the prior conduct must be based upon sufficient evidence; and (4) the prior conduct must not be too remote in time. United States v. Arambula-Ruiz, 987 F.2d 599, 602 (9th Cir.1993). Furthermore, "we must analyze the evidence pursuant to Rule 403 and determine whether its probative value outweighs its prejudicial effect." Id.