ETO Islamabad keeps the following with them: both copies of the Sales Invoice, both copies of the Sale Certificate from the manufacturer, and Form F. And in case of imported car, the copy of custom reciet, reciet of other stuff too and above mentioned three things too.
But for sure u'll get the Registration Letter (Book), and it will be ur property.
In Lahore all the vehicles registered upto LXZ series dont have their file with the owner. But few days back I read in the newspaper add from ETO Lahore that they are in the process of returning the files to the original owners. So in the first phase the owners of vehicles from LXV-LXZ may contact them to get their files back.
My 2000 VTI is LXR case.