Exchange 5.5 & W2k should not load SP2

I have another IT person saying that Microsoft advised him that he should not load SP2 on Windows 2000 when running Exchange 5.5 SP4. That if he did so he would be unable to run setup for Exchange 5.5 again. Which could be an issue if added featureswere needed or in an attempt to recovery the server without a total rebuild. If someone could verify if this is true as the new server we purchased the raid card drivers require SP2.