[CentOS] How do point releases work?

I'm new to RHEL-like distros.

When, say, CentOS 4.1 is released, will it simply be CentOS 4.0 + released 
updates in new ISO images?  Or is it more than just the updated packages 
integrated into the full distribution?

Put another way, if my 4.0 installation is kept up to date with YUM, will 
I basically have a 4.1 installation?

Thanks.