preinstalled Thinkpad R61i - upgrading to point release or has that already been done for me?

I bought my Thinkpad preinstalled with Ubuntu 8.04LTS from linux Emporium. back in June/July 2008.

I have been keeping it up to date with Update Manager religiously, and over the last few days have noticed no new updates coming through. I have also seen mention made of a point release to the OS.

As I am inexperienced with this machine- I do not know how to update it apart from firing up Update Manager, clicking on "Check" and "Install Updates"... but am I going to receive new bugfixes?

Does this point-release thing work in a similar manner to Service Packs? Or have the relevant bits already been downloaded for me, as I did see three sections in the Update Manager about 2-3 weeks ago...

"Security updates", "Recommended updates" and "Distribution updates".

In the Windows world, Service Packs are sometimes released through Windows Update, and the customer does not have to do anything except update as per usual. Does this work the same with Linux?

I am scared that I might either be leaving my machine susceptible ot new bugs and will not be able to collect bugfixes... will my machine still be updated.. or should i send it back to my vendor for reinstall to the new Service Pack...

How DO point releases work - are they Service Packs?