Como você está no início do processo, eu provavelmente optaria por refazer a restauração em vez de tentar "consertar" as duplicatas. Apenas para evitar possíveis efeitos colaterais.
Encontrei esta "lista de perguntas comuns" sobre o backup e a restauração de tags de nome aqui:
Como fazer o backup das tags de nome e copiar para outro compter
Thanks for trying out Picasa 3.5 and thank you for your posts! We've put together this list of common questions on the topics you've addressed that we hope will be helpful to you.
Q: Is face tag data stored in the photo itself?
A: We currently do not store face tag data directly inside the photo but this is functionality that we hope to have in the future.
Q: Since my face tag data is not stored in the photo itself, where is my face tags data stored?
A: Face tag data is stored in the Picasa database and also in the .picasa.ini file in the folder where your tagged photo sits. To see the location of the photo on your hard drive and the .ini file where the information is stored, right click the photo and select "Locate on Disk".
Q: How do I transfer my face tags from one computer to another?
A: There are a few different ways to transfer your face tags:
1) You can perform a Backup of your photos and restore them on your new computer. This process will preserve your face tags. ("Tools" > "Backup Pictures") 2) You can copy your files and the .picasa.ini file from your hard drive to the new destination 3) Upload your face tag albums to Picasa Web Albums and download the album to the new destination