It is still possible that is does have OIS. Just because they are using the same focal length of 23mm doesn't mean that they haven't introduced OIS or a larger F stop. While it does make sense that a company would choose to use something off the shelf to save money, companies also know that if they don't indicate they'll get left behind. If this weren't the case Fuji would just be making more x100v to fulfill demand while it was HOT. They sold through their run, and with the chip shortage, decided to focus on the x100s(6) instead of making more 5s ensuring that demand for the new model would be high.
Also, the body could have IBIS and digital stabilization or some entire combination of the 3, because having a fixed lens could allow a Fuji to do things not possible with an ILC system.