The 90 bumpers bolted right to the ends of the frame horns, when they changed body styles in 92, the frame horns were boxed with flanges attached to the inside edges that held up the bumpers. It could be done, but as mentioned some fabrication will be needed. Also consider the 90 body style was more boxy, not curved like the 93. Here is a picture of the 80-91 style frame horns.
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