No, I believe it's the MCs that are more tolerable to overclocking.
That being said, I think the Blizzard is a better board. More reliable and slightly more expandable (SCSI Kit). I wouldn't recommend overclocking for either board though, since these things are so rare. Better to keep them running longer, if slightly slower, in my opinion. Overclocking just risks damaging them for a not-so-significant speed boost.