If the files were not in pdm, you could add a suffix/prefix by using Pack-and-go. I don't know if that would help in the data cards.
What field on the data card do you have Part Name linked to? Is it linked to SWFile Name using the Input Formula of FileName - that would fix new files moving forward.
You could write a dispatch script to update them with a right click - or when you send them through a transition.
The other option is to do a mass update using the API.