i can see that, especially since the term 'prerunner' is so open for interpretation. heck, some teams used to use rental SUVs to prerun their courses. a prerunner can be whatever you want. most agree however, that a prerunner has to be a street legal vehicle that can pre run a baja course at a decent speed, so supple suspension is a must, unless youre ok with being limited to 25mph. with speed comes a cage. tire size, fiberglass bedsides, lightbars, etc are up to the builder.
so yea, it can be whatever you want it to be.