Thanks for your question.
Yes, you can move the PCB's just as any other object in FAB 3000.
Select the PCB Inserts, and use the command Move. FAB 3000 also accepts relative and polar coordinates for easy movement of objects. Please view the following link:
Note: You can also globally adjust the placement of any PCB in a panel, by using the command "Edit Inserts..." (menu: Job / Edit Inserts...).