Yes, it's true that the statute is titled "Assaulting, resisting, or impeding certain officers or employees." But every conviction under 18 U.S.C. § 111(a)(1) has an essential element of assault. So said the Tenth Circuit last week in United States v. Wolfname, finding that a district court's failure to instruct on the assault element was plain error necessitating a reversal of the defendant's "resisting and interfering" conviction.
Draft your jury instructions accordingly.