If it describes or is unique to the file, it goes on the file card. If it describes or is unique to the folder/project, it goes on the folder card.
A part number almost always goes on the file. This way your searches and reports are more logincal and you can put that information in the file properties/titleblock.
You could do both...if the folder/project has a number, it can be on its card, and the parts number can be on its card.
Thanks so much for your response. I was thinking that was the case, but it helps to get an outside opinion. And thanks for the suggestion of placing the project number and the part number on the folder and file cards, respectively.
Thanks for your time and help.