5.5 Upgrade Without Uninstalling Packages

[Chaz Gilbert]

Hi All,
Why yes, I'm an idiot.  I upgraded to 5.5 AMD64 via CD just now without reading 
the instructions.  As a result, I didn't first uninstall the packages that were 
on my 5.4 system.  Do I have any recourse now?  Can I just delete the packages 
now and rerun the upgrade?
Thanks for any help.
-Chaz