Yes, it is the hubs that have to be machined. Daryl, there may be a problem using the Pontiac hubs. According to Touring Classics, some have a different offset. I checked my stock hubs and they would not work so I found a set of hubs from a 68 Camaro. I did not use the Touring Classics front kit (I do have their loaded calipers)but I am using their rear kit.
You can get all of the parts and save a lot of money. With all new parts, including master cylinder and Stainless Steel braided lines I have just over $500