Yes. I tried taking out the batteries and resetting the controllers without any luck. Neither controller was able to pair with the FBX. Not sure if there's an issue with the frequency or whether the antenna is even active/functional.
I wanted to follow up on this thread. I ended up purchasing a used FB9 Gold and it turns out the FBX did not recognize the wireless controllers. I tried updating the FBX firmware just in case the newest version had wireless capabilities, but still no luck. I would love if anyone could figure out a way to make this work, if it's possible.