Omega Reply
They are basically the same. The Z5 version is a no frills gun. The regular Omega, to my understanding, has a fluted barrel option and comes with a wide variety of stock and finish options. The Z5 is a black stock/blued barrel gun. It sounds more like you have the regular Omega. Did you buy it new or used? Both versions do use the same "action" and accessories. I have the Z5 with the black stock and blued barrel. Hope this helps.