Managed Software Delivery

I have question about managed software delivery.

EG : If there was a software deployed to a machine let say (micosoft Office). This software is downloaded to the machine and instlled succesfully. The user un-installed the application from the machine but the downloaded software is still there in altiris dirictory. Now if i re-deploy the same package using a new managed software policy will the package be downloaded again on the machine ?

So my question is if the a new policy is assigned with the same package which is downloaded before will the client download the package again to the machine. Is the package downloaded based on Policy GUID or Package GUID ?

Thanks for help