Don't forget the little clip that holds the pivoting end of the fork to the ball in the bell housing. You can do without it, but if play develops and it's not there or broken, the fork can fall out of place.
The clutch pedal mechanism in the 93 differs from that in the 97. EArlier ones have a second arm for the MC welded to the pedal arm, and later ones use a pin directly on the pedal arm. I think the master location may be different, but I have no XJ's here at the moment to measure. I don't know if it is just an upgrade or whether it requires some modification to fit on, but be prepared for the possibility that you'll have to do more than just plug it in. The 97-up mechanism is less prone to problems, so if you can use it, do.
Earlier XJ's had no interlock on the clutch, but my 99 did. Your option whether you wire it in (same circuit as neutral safety switch) or skip it and short the NSS connection.
Are engine computers the same for both transmissions in 93?
I have put a 95 Ax-15 into a 99, l so I know that works fine. I encountered no basic problems, and if the tranny is good, I'd just make sure no water gets in while it waits, and put the right fluid in it when you finish the job.