If fossils were consistantly found in the geological column out of any order, as creationism would predict, then yes this would have falsified evolution. Look at the time period following the publication of On the Origin of Species, for example. The fossil record was poorly investigated at that point, and could have resulted in falsification of Darwin's theory, if fossils were then found to be in random (though ecologically logical... e.g. marine organisms together) order. If a bunny were found in Precambrian rocks today, it would be considered an anomaly, rather than a refutation. If, on the other hand, bunnies were consistantly found in Precambrian rocks, it would indeed be a big problem for common descent.