There isn't a publicly available record of the absolute *worst* MCAT score ever recorded. The MCAT score is a composite score, and the AAMC (Association of American Medical Colleges) doesn't release data showing the lowest possible score achieved. Furthermore, the scoring system has changed over the years, making direct comparisons across different eras difficult.
While a theoretical minimum could be calculated based on the lowest possible score in each section (though there are no published absolute minimums for each section), the actual lowest score achieved remains undisclosed.