Yes, /admin/deliverydates (not linked in the menu; admin login required) shows a Delivery Dates table with Date and Weekday columns and Copy / CSV / Excel / PDF / Print buttons, which is handy for exporting your calendar. In the current version the Add new button and clicking a row open an Edit Delivery Date window that contains no fields, so the page is read-only in practice — creating dates is done by Sprwt staff (see "How are delivery dates created?").