I would be surprised if they work with the stock starter. I had a set made for the 85 and for the 87 just to be safe. But as far as the steering I would think they would be fine.
It has something like it. That's what keeps you from starting it without the clutch pushed it. My TC had one.
https://lmr.com/item/LRS-11156A/86-93-Mustang-Clutch-Pedal-Safety-Switch