'Location' nodes created before installing GMap don't display map. 'New' location content does.

I created a site with a custom node type 'location'. I created dozens of location nodes, they display just fine. I thought it might be nice to roll a map into the node template, so I installed GMAP, configured the Geocoding, set up the views (as I have on numerous sites in the past) and then configured my node template variant for the location node type.

I loaded up one of the location pages and got the address etc, but no map. I triple checked everything against my other sites with working GMaps and everything is identical. After redoing the view, clearing the site cache, and even trying other themes, I remembered something similar happened to me back in early D6 and pre-existing content (location nodes created prior to GMap install) didn't work, so I decided to test the theory.

I created a second location type 'location2' and added location2 to the view's content type filter and the node template variant's selection rules and wouldn't ya know, the map shows up in any node created following the GMap install!

I went back to the original 'location' content type opened a node (created pre GMap install) and no map, even after page refresh, browser cache clear, site cache clear, unpublish/republish... everything I could think of.

With 80+ of the original 'location' content type nodes created, I would be a huge bonus if I could get the pre GMap created content to display the map somehow rather than retype volumes of information.

Any thoughts? Thanks in advance!