IIRC, someone on here or EF ordered a Hellwig 7648 from SD Truck Springs. Said they were made to order and could take a couple months. Used Explorer Express "X-Spec" 1-1/8" rear sway bars are extremely scarce. I've been looking for years to replace my Addco 633 I currently have installed. IMO, upgrading the stock undersized 19mm (3/4") rear sway bar was by far the best handling and safety upgrade I've ever done next to tires and shocks. However, if you have a lifted suspension, rear sway bars limit articulation when off road.
May want to contact SDTS if interested.
https://www.sdtrucksprings.com/index.php?main_page=product_info&products_id=3748