Iowa Code § 558.42: Acknowledgment as condition precedent.

A document shall not be deemed lawfully recorded, unless it has been previously acknowledged or proved in the manner prescribed in chapter 9B, except that affidavits, and certified copies of petitions in bankruptcy with or without the schedules appended, of decrees of adjudication in bankruptcy, and of orders approving trustees’ bonds in bankruptcy, and uniform commercial code financing statements and financing statement changes as provided in chapter 554 need not be thus acknowledged.