Hi,
The export/import system does not handle all options of product files.
If you want to change the default values, you have to edit the helper import and see the function "_insertFiles".
You will see that the SQL query insert several values but not all values.
INSERT IGNORE INTO #__hikashop_file (`file_name`,`file_description`,`file_path`,`file_type`,`file_ref_id`,`file_ordering`)
If you want to set the default values, you can specify them directly in the database. By setting the "default" value for the column.
Otherwise, you can update the query in the helper import.
Regards,