Hehe, Xerox, like the copier company?
Probably just someone elses memory and they slapped
their name on it. I can't imagine Xerox getting into the memory
world. What does the individual chips say?
Generally good memory will not "fry on you". Bad memory,
well, it's going to fry on you eventually wether you OC it or not.
It can't hurt much to push the memory beyond it's specs and
see what it can do. As long as your not pushing the voltage too
high, the worst that could happen would be a hard drive
corruption from a bad overclock or the memory chopping up
data. IMHO, that's a small price to pay to find the limits of
all your hardware, and properly "tune" your machine to it's
(safe and reliable) limits.