all the 88-91 preludes that HAVE 4WS will have what looks like a rear drive pod in the back underneath about where it would be if it was a drive pod. it says 4WS on it
also you can turn the wheels lock to lock and the back wheels will move.
I would think if you have it, you know it.
I have a 1990 with 4WS. it's awesome, and while I wouldn't trade it for anything, it DOES have 205,000 miles on it, so I may have to