No. The updates can start to show up even a day after release because the
final release is usually finalised up to a week in advance of the release
date.

You can create your own image of many distros using something like
Reconstructor or Remastersys. Just install a distribution, do all of the
updates and then create an ISO image from your computer using either
application.

linux.softpedia.com/.../Reconstructor-16806.shtml
http://en.wikipedia.org/wiki/Reconstructor
http://en.wikipedia.org/wiki/Remastersys
www.geekconnection.org/remastersys/ubuntu.html