It looks like akondi and the previous versions of Kontact use different standards for storing vcf data. Kontact stores these data in a single file at:
/home/.kde4/share/apps/kabc/std.vcf
Akondi uses individual .vcf files located at
/home/.local/share/contact

It looks like the default address book is using the former technique, and not the latter. The time stamp for std.vcf is today. The time stamp for the files located at /home/.local/... is August 8 of last year.

Am I correct in backing up the std.vcf file, only?
Are the files of /home/.local/share/contact of any value?

Of note the script command I am running is:
cp /home/user/.kde4/share/apps/kabc/std.vcf /windows/E/std_`date +%Y%m%d`.vcf;
This saves the file on an external USB drive.

Thank you in advance for any assistance.