Im not sure how the Chinese make their stuff so cheap (unless it is slave labor with no environmental or worker safety regulations).
That would probably work, but as simple as the regulator circuit would be, and for no more than what you need it for, I would go with the regulator, but its entirely up to you.
Also, you probably wont need a heat sink but it sure wouldn't hurt to use one if you have one laying around. be sure to put a drop of heatsink grease on the two mating surfaces or you are probably wasting your time.
If you do go with the voltage regulator, I would use the 6 volt one, since the Namco wants 6 volts.