Is it possible to get a unique identifier for a photo during the Aperture export process?

I'm attemptig to build a custom aperture exporter to get all my photos out so I can migrate to catalina. It would be extremely useful to be able to get a unique ID for each image as it's being exported. It looks like the export plugin idetifies images via an index which is relative to the export; is there a way to get some kind of a uuid for each image? I assume aperture must somehow identify images internally.