Most 670's would have its stock volts at different levels -- it depends on the components on the PCB that the manufacturer uses, which is why certain components on MSI cards make them overclock better, as they are better quality.
So basically what you get is what they have deemed safe. Their three year warranty also shows they stand behind their products, and trust me, they have good warranties. One of my friends had his MSI 6950 take a crap on him, they replaced it with a 7950 completely free of charge.
And yes, it is pre overclocked I believe.