The Hibben throwers were designed by Gil Hibben but made by United Cutlery. United Cutlery filed bankruptcy and closed down in December 2006. Dealers bought much of the inventory. The remaining UC assetts and trademarks were bought by Buk K (the knife catalog company). I have been told that Bud K intends to continue the UC line of products and the United Cutery name but I'm sure it will take months to get thing in production again.
Bud K did not get the licensed products as part of the deal (Hibben, Kit Rae, Lord of the Rings, Rambo, etc). The license holders for each of those lines will negotiate their own deals which may, or may not, be with Bud K.
So, to answer your question, the United Cutlery Hibben knives are not being manufactured at this time. I would be very surprised if another company didn't pick up the product line but no deal has been made yet. I am sure there are a lot of the Hibben throwers out there in dealer inventories and I would think that you can find better deals.