Yes. To do this you will have to manually turn on EveryDoor for each booking you made before signing up. Follow these steps:
1) Visit the Bookings page and click on a booking in the calendar you would like to use EveryDoor for.
2) Scroll to 'Host Sign Off' section at the bottom of the page (after ensuring all other fields are completed as desired)
3) Enable EveryDoor check-in automation by selecting YES!
4) Repeat as desired for other properties.