Dont even bother using the values reported by the bppcs' firmware. They are just values written into the flashrom and there is no guarentee they are correct. The actual speed is determined by your ppc's clock crystal and a multiplier, both of which are set in hardware and not adjustable from software.
If you want to know for sure, you need to check your crystals on the bvision and also know what clock multiplier is used on the ppc. The multiplier is tricky to judge, there are 4 surface mounted resistors just below the crystal that determine it. I can't remember of the top of my head how they are configured, but you can find out (search goodgle for "blizzard ppc overclock").
Alternatively, have a look under the PPC heatsink to see what the ppc chip is rated at. If it's 200MHz+ you can be reasonably sure it's not a 160MHz version :-)