There's nothing to worry about. There are just two steppings of the 3700+. The E4 stepping has a voltage varying between 1.35V and 1.4V while the newer E6 stepping runs at 1.35V. Either way it doesn't really make much of a difference. The voltage fluctuates anyways.
Also a) PCAlert tells me my cpu runs at around 55-60+*C, is this normal?
b) PC Alert tells me my +12V rail is 6.49V sometimes I see it's 5.49. This doesn't sound right at all, but my PC seem to function ok. Should I be worried??
There are two steppings for the 3700. The original San Diego came in 1.35-1.4 vcore, E4 stepping. The new E6 stepping uses a staight 1.35 vcore. While some of the original E4 steppings could use 1.35v, not all could.
That means you may have an E4 stepping, or one of the newer E6s.
Sounds like your sensors are being read wrong. Try downloading prime95, and running it for a couple of hours. Then tell us how high your temps get, according to pcalert.
You might want to see if you have the choice of more than one sensor for your 12v rail, and your cpu temp.
Since sensors dont get calibrated (ever) it is not all that uncommon to get one or two that read wrong.