in 1989, ABS was an option. HICAS was not available until 1991.
http://www.socal240sx.org/faq/1989.html
Couple of ways to tell. Follow the brake lines from the Master Cylinder. If they go straight to the brakes, then you do not have it. If it goes to one place(might look like a big junction) that has a bunch of brake lines and some wires coming out of it, then you have ABS. If you remove your front wheels and there is what looks like a gear behind the brake rotor, you likley have ABS. If lift your rear end and look at the nose of the diff, and see a sensor in the front of it, you likely have ABS. When you turn your key to the on position, if you see an ABS light, you likley have ABS. If you check the fuse box and you have a fuse where it says on the diagram for ABS, then you likley have ABS.