At the moment, reservation booked within 48 hours, and guest can choose the check-in time
https://help.hostfully.com/en/articles/3811657-partially-allow-booking-requests-on-airbnb

The check-in time should be visible in the booking request that Airbnb sent, not in Hostfully system. Airbnb does not send anything explicitly to the host stating that the check-in time has changed; however, the reservation request Airbnb sent to the guest does include the check-in time.

We need Hostfully to request this information thru the API and indicate it somewhere in Hostfully system so we can know before accept or decline the booking request as it's very important information to look at