Facebook Messenger has allowed users to add Instagram accounts but has no option to sync them at this time. This feature is presented to replace the basic Account Instagram option that can be found in the Profile menu.
This feature has been available in a number of limited user accounts who have Messenger and Instagram. This indicates that Facebook is actively testing this synchronization options to find out how it works in the real world.
Time-related information is not yet available for all users the availability of social networking platforms. Based on the previous history, this feature will not be promulgated until found and shared by the user.