The subject about ABS came up in the forum not too long ago and I don't remember anyone saying they had done that conversion on a Fiero. It wouldn't be impossible to do but it, but it would be quite a bit of work. I think you'd have to add wheel speed sensors on all four corners and figure out the electronics of it all.
It should be pretty easy to tell just by following the brake lines around the car and looking in the front compartment.
Sounds like she bought the car and the person she bought it from didn't know either or added some extra fluff.
Speaking of non ABS traction, last week I got my Fiero sideways going too fast on a wet exit ramp, guy behind me probably though for sure I'd spin'er around, but I held on. Most fun I've had in a long time, it was funny making a left curve turning right! 
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T-T-F-N, Tah Tah For Now!
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