I'm talking about the days when the MCAT was known as the PSAT in the 1940s. The mentality was that you didn't have to prepare for it ( ie. No prep course or practice tests) because it was supposedly based on many years of past schooling so if you didn't do well you were essentially screwed and there sure wasn't an MCAT prep course or commercial practice tests back then... However, things are very different today and you said so yourself that it would be foolish not to prepare for either of those exams.
Countries like Canada and the UK have been using CASPer like tests for years and many of their applicants prepare in the way you would for the MCAT.