Not exactly. When importing .csv files there is the need to correctly identify the file, so the path and the filename, or the fullpath, fields are really necessary.
The disk serial, volume label and disk type are also other fields useful to make the correct identification of the file source disk, in multiple and removable disk, systems. If these ones are not provided they are gathered by the import tool from the disk corresponding to the drive letter of the provided file path.
If the file is already indexed in the database, all the not provided fields are keep unchanged. For new files, not yet indexed in the database, (PDF Explorer can import .csv files from other cataloguing systems) these not provided fields are filled with default information, for most of them, empty one.
So, you can export your custom grids, but the file path is necessary. If you are using a custom grid layout, with the "Hide invisible fields form the rest of the interface" option active, and the file path field is one of these invisible fields, you have to temporally uncheck this option so you can export that file path field.