For some reason, searching for “wincvs revert” in Google doesn’t immediately show http://cvsgui.sourceforge.net/newfaq.htm#reversion, which it absolutely should. It explains what you have to do, but to make it extra clear here is a screen grab:
You can replace HEAD with another version like 1.12.
BTW, if you’re on Windows and using Eclipse, WinCVS is a great support tool for Eclipse’s broken CVS support.1 I can get history/logs for files and revert to previous versions. Eclipse remote history has been broken for me through several upgrades/reinstalls and will only revert to a tag, not a specified file version.2
The only real issue I have with WinCVS is that its help system doesn’t provide any. Expect things like “Merge options dialog allows the user to change the merge options.” Still, I’m grateful for the effort and can’t complain about the price.