I would put a small safety hole if the duckling doesn't pip in the next few hours as a precaution, this late after internal piping it shouldn't hurt anything if done correctly. Chirping back might encourage them to pip too.
Here is great link regarding assisted hatching-
https://www.backyardchickens.com/articles/guide-to-assisted-hatching-for-all-poultry.72886/
Here is great link regarding assisted hatching-
https://www.backyardchickens.com/articles/guide-to-assisted-hatching-for-all-poultry.72886/