How to access data from a Mac Contacts backup: a .abbu file
If you have iWorks/Numbers installed, check the tutorial:

How to Convert an Address Book ABBU File to CSV
ABBU is the native file type for the Mac OS X Address Book, which means that you can only open ABBU files using the Mac Address Book application. However, you can use the iWork Numbers application to import the ABBU file, and then export the data file to a Comma Separated Value, or CSV, file format, which is a generic text file format that you can import into any address book or database application, regardless of operating system.

Also you could try the tool:

AB2CSV
Also known as Address Book to CSV Exporter, this Mac OS X utility allows the user to export his own Address Book in a CSV or VCF file.

You did mention &quot;vs just importing them&quot;, but if you can use the first method to export them to Numbers, you can then save as .CSV.