Hi,
Yes this is possible. I am not sure why you created the packages with updates turned off, I assume it suited at the time, the reason I bring this up is. By using the Enterprise IT Tool RUM (Remote Update Manager) you could continue to keep updates turned off so the client doesn't manually try and bring them in but instead only does so when you send a command to the clients. The command would be issued to clients through a 3rd party deployment tool like SCCM, Casper, Alteris. This way they are installed as admin and only on your designated schdule. This might not be appealing but I wanted to make you aware of it. The Enterprise Deployment guide will give you more information about the overide file required to change the update options and RUM can be found in Adobe Labs http://labs-staging.macromedia.com/technologies/aameetools/
Cheers
Karl