Both my 89' hatch and 93' convertible had the fiberboard underneath the rear carpet and inuslation with a sticker attached to the fiberboard showing the correct way to jack the car up and etc. My Cobra has the fiberboard embedded in the rear insulation under the carpet. It was a new one to me.
Mine's the same as buddha93- a smaller than normal piece of fiberboard sandwiched between layer of glued together insulation.
My '90LX hatch has a larger piece of fiberboard with the sticker on it on top of the spare and beneath the insulation like most other foxes.
I always wondered why the cobra was different.