When Omaha recognized the Nebraska Permit to be able to carry concealed in Omaha they also recognized it as being the equivilant of their open carry permit, so you do not need the OC permit to open carry if you have a CCW.
The note from the National Safety Council, they want your $100. From the comments I have heard from people that took either the CCW course or the open carry course from them is their classes are poor and are just a way for them to discourage people to carry firearms while takeing your money.