Whenever you alter the designers original intent, there are nearly always serious consequences. Best case, I'd say that your boat is going to be crippled going to weather. Worst case is that the centerboard weight being in the hull will throw off the balance of the boat...making it a lot more rolly. On the positive side, 4'2" will get you nearly anywhere in Florida and Bahamas...perhaps this is why the PO did the modifications.
Also think about resale...this is the equivalent of putting on an unpermitted addition to a house. Some people wont care, but most will run away from buying this boat.