Object Copy - Data Flow/Zoning Query

Hi All

We have a requirement to create some post backup object copy jobs, to a physical tape library.

Backups currently back up to VTLs presented on a StoreOnce Backup array.

Question 

When the copy job runs does the data get copied from the VTL to the physical tape or will it just copy again from the source like a normal backup?

I am in the process of planning for the Physical tape library zones, and wondered whether it simply needs zoning into the VTLs on the StoreOnce or if it needs to be zoned into a media agent?

Many thanks