I just tried it, and it seems to work.
You can export the entire library from to "settings" --> "export" --> "export to CSV".
If you just want to export a single folder from your library, you can use the dropdown button next to the folder name in the Paperpile library.
The resulting file will have all the characteristics listed as colums.
Labels are saved in a single column "Labels filed in".
So a single cell contains multiple labels, separated by ";".