89 - 92 calipers bolt directly to tabs on the spindles. 93 - 97 calipers sit in an anchor which gets bolted to the spindle ... so they are not interchangeable.
The ABS sensors are different between the early and late style as well, but I don't remember if there is a fitment issue or not. Try doing a search on the topic if you haven't, lots of people have put later spindles on earlier cars to do brake upgrades, see what they did with the ABS.
cheers,
Ed Nicholson
SCCoO