InfoPath Dev

We recently enhanced a browser based form and added code to it.  Prior to the modification it was a straight deploy to a form library in MOSS.  After the code was added we deployed it as an admin deployed form but now appears to be a new content type and the forms sumitted prior to the change show the old form and the newly submitted forms reflect the latest changes.  Is there a way to deploy an admin deployed form (with code) to the existing content type or merge the new changes into the old one?

relinking the old forms should do the trick, go to the document library -> settings -> document library settings -> relink documents to this library

and select the documents to be relinked.

The re-link option only shows 4 forms, and they are of the new template recently uploaded.

The old form template is still on the site, but hidden in the menu.  Does the old form (content type) have to be deleted from the library first?  Will I lose data that way?