[nova][neutron][openstacksdk] Any API way to tell the difference for openstack ports created manually or automatically?

I could not find any API way to tell the difference between openstack ports created automatically when a new instance got created, and openstack ports manually created for port reservation purposes. There's 'preserve_on_delete' attribute in the openstack database for each vm instance, and if it is set to 'true', then the port was manually created, if not, then it was automatically created. But there's no API to retrieve this. Am I missing something? Hai