Sorry, I don't have an authoritative answer, but I would use a little common sense. If the install is throwing up warnings (like it used to do) about incorrect disk geometry then I would cancel the install and restart it manually specifying the correct disk geometry. It shouldn't hurt to manually pass the correct disk geometry to the installer.
For what it's worth, I had no problem installing/upgrading FC4test3 over an FC1 install on my dual boot (WinXP) laptop. Doesn't mean to say the bug's no longer present though