Red Hat :: Finding A Command That Generates A Report Or Allows To Check If Certain Updates Has Been Patched

I currently have Red Hat 5.4 installed and subscribed to red hat network for alert updates.The updates will be done by our administrator but I will like to check if the admin has done so on a weekly basis. Is there a command that generates a report or allows me to check if certain updates has been patched? I understand running a yum update will list all applicable patches. Should we just simply update all or only certain applications applicable to our organization environment?