At least one of the Janet -600s is equipped with them.
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Other than the attached photo, the only other photos I found of their aircraft on the ramp are at LAS with traditional airstairs attached. Satellite imagery of the aircraft at XTA appear to show traditional airstairs as well.
The Navy C-40As are equipped with them. As are the USAF -40B/Cs.
Not sure if you'd count factory-built BBJs, but integral airstairs would have to be a standard feature.
Make Orwell fiction again.