Open it up and look. Just because it's a SMB board doesn't necessarily mean you can't modify it. If there are wire leads and you are good with a soldering iron you are home free. If the pad lengths are long enough to be cut and wires added to reverse the motor and the potentiometer leads you are also good to go. It should be rather obvious and you are the best judge of your abilities. If you've never had a servo apart or put a gear train back together and you are all thumbs it's better left alone. In my opinion its better to buy a Match Box or a digital Hitec servo and have it reversed if you have doubts.
John