[CentOS] patches and current CD's [dnk]

I was reading another thread, and this stuck out at me:

"This issue was fixed by the CentOS team
(and integrated into our install CD) prior to it's release by the
upstream provider."

As patches and such are released - are they integrated into the  
current CD's right away? So say for example, I downloaded the server  
CD a few months ago, then re-downloaded, would the patches from point  
a to point b already be integrated into the cd's?

Thanks!