That looks right, assuming you are in the Eastern Time zone.
The exact timestamps will depend on which timezone you are asking for because the start of the day moves around depending on where you are in the world.
These timestamps are in Coordinated Universal Time (or UTC), and 4:00 UTC corresponds the midnight at start of the day in the Eastern Time zone. The timestamps are also returned in UTC, so you’ll also need to be aware of that and make the conversion to the date of your desired timezone.