My salesman called about a radio part?

So I recently got a used Subaru , and the touchscreen on the radio is weird , most of the buttons don't work so I just keep it on Bluetooth. My salesman called and said he had a part for the radio that came in that I can bring the car in and he can put this radio part on. I want to trust the guy, but what are the odds that this "radio part" he says he has for me is actually a serious problem with the car , that jeopardizes the car and he's just calling it a radio part to not arouse suspicion ?