Hi,

By default, Odoo does not preserve a file’s original creation or modification date when importing; it only records the upload date (create_date). If you want to keep the original file date, you need to add a custom field on attachments or documents. This can be done manually during import (via CSV), through a small customization that extends ir.attachment to capture the file’s metadata automatically, or in the Documents app by adding a custom property such as Original File Date. In short, Odoo always records when a file is uploaded, but retaining the original file date requires an extra field and configuration.

Hope it helps

Hi,
All files and their data are in the [Developper mode activated] 
→ settings > Technical > Attachements > open a file and you have the create date visible there.

I just verified and the files has a date field you can place on the list view (attachements)