I’m runing LibreOffice on my mac and i’m the sucker at the office to always print the new labels.
I recently reinstalled my laptop and lost my label settings, it took me a while to find where LibreOffice saves the templates but i finally found it.
Turn of your LibreOffice, and on your old disk go to
cd /backup_pad/Users/<username>/Library/Application\ Support/LibreOffice/3/user
Copy the file to your new disk.
cp registrymodifications.xcu ~/Library/Application\ Support/LibreOffice/3/user
Restart LibreOffice and you should find the labels you made again.