If the cost of any insurance is to be separately charged to the buyer, there shall be an agreement to that effect, signed by both the buyer and the seller, a copy of which shall be given or furnished to the buyer. Such agreement shall state whether the insurance is to be procured by the buyer or the seller or holder. If the insurance is to be procured by the seller or holder, the seller or holder shall comply with the provisions of § 4307 of this title.