I have a feeling that apps will have to be downloaded a second time to the second device unless the second is a replacement and registered on the same BB ID. Otherwise how would Appworld know which one needs the app upgraded? Also, paid-for apps probably are only available for one device at a time.
On the 'new PB, temporally you have to change the BB and appWorld ID to the 'old PB's' ID
On the 'new PB':
Open the home screen icon: "HELP"
"Blackberry AppWorld"
Update your Blackberry ID account information go to ...
Use the 'old PB' ID information
Then, when you use the 'old PB' ID you will see all the apps installed on the 'old PB'
INSTALL
Should be able to install the selected apps on the 'new PB'.
If you change the information back to the 'new PB' ID I am not sure if the paid apps will be able to update.
If updates are available, you might temporarily have to do the same change ID again.
I plan to use my existing BBID on my new device and after switching, create a new ID on the old device. Has anyone actually used the Switch Device wizard to do this? Just curious before I invest an afternoon in trying.