Please perform the following to view between different jobs:
1. Create a New Job (Menu: File / New / Job...) and name it after your first part number.
2. Import all data from that job.
Note: If Gerber/Drill, try using AutoLoad (menu: File / Import / AutoLoad...). IF ODB++ than use ODB++ Import (menu: File / Import / ODB++)
Once you have loaded your first job, now lets create a second job and import data into that.
3. Create a New Job (Menu: File / New / Job...) and name it after your second part number.
4. Import all data from that job.
Now you have two jobs imported into FAB 3000. You can do some cool things such as:
(A) Toggle the tab to view data for each job.
(B) "Compare Jobs" (i.e find differences between the two jobs if they are similar) - menu: Tools / Compare Jobs.
(C) Create a Panel which merges both jobs together.
Let me know if that answers your question.