Edub9,
Sorry I am confused by your request.
You say you need to migrate this into K2, yet you replied that is not what you need.
Can you please clarify?
If you only want to import the zip codes from Joomla, then this is a way.
You will need to Archive any Joomla data you do not want to import, then carry out the import and unarchive the joomla content.
or
Import all data in to K2, retaining 100% data as live, much safer.
Then trash everything you do not need, leaving just the zip codes.
Hope that helps.
Simon
K2 Support