Yes, I believe you have to run the nvidia update script/exe when ever you upgrade your kernel.
Two points. The nvidia updater is pretty nice now in that it will download prebuilt drivers for your kernel version if they exist, or it will try to compile the drivers for your kernel version. Of course the later requires that you have the kernel source installed! I believe for RH the kernel source is not installed for their basic installations. You either have to install everything, do a custom install and select kernel source rpm or lastly find the kernel source rpm on your distribution media and install it your self.
The second point it for RH and their updater program, I believe you can tell it not to update and kernel packages automatically. You might try this to avoid accidentally updating your kernel without realizing it.