As I understand it, and I may be wrong, these files actually include backups
of the original file versions, allowing for both uninstallation of the
service pack and reversion to the original OS state. As such, you should be
very certain that the patch is causing no problems and that you will not need
to uninstall it. Considering this, I usually wait until a service pack or
interim patch is proven safe, and then consider deleting the PRIOR uninstall
files, leaving the most recent one just to be even safer.