"Not at all" would be the correct answer. nvidia-switch is only for the userspace part of the nvidia-graphics-driver. Rebuild and install your new kernel, then run the nvidia-kernel script again. Something like this should work:
Code:
KERNELVERSION=2.6.24.new ./nvidia-kernel.SlackBuild
This will generate a nvidia-kernel package for the new kernel.
If you want to keep the old kernel-module be sure to install the nvidia-kernel package using "installpkg", as "upgradepkg" will delete the old one.