Yes, you can change the File Type Access field at the time of file upload.
- Go to the Record page → click on the Upload Files to Amazon S3 custom button.
- From the Select Type of Access picklist, you can easily change the type of access at the time of uploading the file to Amazon S3.
PS: View Drag, Drop & Upload Files to Amazon S3, a Salesforce AppExchange app for moving files from Salesforce to Amazon S3: https://appexchange.salesforce.com/appxListingDetail?listingId=a0N3000000B5ZPqEAN

