Content Delivery API - get numeric node ID

Hi everyone. I have some legacy data from V7 migrated to V13 that requires using old int node ID and I’d like to access it using the Content Delivery API.

However, can’t see it anywhere so I presume this can’t be done using the fields query and requires building a custom selector? Alternatively I could copy it to a custom property but I’d rather stop bloating the database.

Thanks for any pointers.