Is it possible to see where the oab files are located Outlook uses?
Yes. If you want to know the location from where your Outlook profile retrieves its Offline Address Book entries, you just need to create a new mail message, click on To. You will get a pop-up windows entitled Select Names, and there you can right-click the Global Address List, and select Properties. You will then be shown the Microsoft Exchange Address Book Provider, and see the current server, which will show the location of your Offline Address Book files, and the directory hierarchy path for that container, that is by default set to the Global Address List.