Like Bob says the grease gets cooked on FE equipped Shelbys and Mustangs because the steering box is right next to the red hot exhaust manifold all the time. Yours might be OK or not but certainly if you have never replaced the grease there isn't any.
The good news is the steering box can be removed with the engine in the car. Probably the worst part of the job is that there are so many components to remove to make it happen. None of them are hard, it's just that there are so many things.
The box can be refilled with grease without removal but that means the old hard clumps of cooked grease are still in there. Not a great way to do it. Generally removing the box and tearing it apart for inspection and cleaning you will find lots of wear even on low mileage examples.
With only 32,000 documented miles on the clock I wouldn’t have thought the components inside would be worn.
Is there any way of testing for wear?