Unless you have a huge heatsink to put on the backside of the circuitboard, I would say absolutely not.  You'll do more harm than good.  The casing IS the heatsink.  If you want to take further 'cooling measures' then replace the stock thermal paste with some good quality non-conductive/non-capacitive thermal paste and add some small heatsinks to the tops of the chips and add a fan to blow through the chamber.