As for what's mailed to you after accepting your appointment --- an "Instructions to Appointees" booklet that has all sorts of info in it should come beginning end of Jan early Feb. It gives you your PO Box you'll have while at AFA, immunization record form is in the booklet that has to be filled out and faxed/mailed back, checklist of what to bring/not bring with you, the Orientation information folder, info on sponsor program, AOG, bank form to be mailed back to open your Armed Forces Bank account (required, but lots will change their direct deposit to another bank after classes start).
Our son's nice appointment certificate was presented at senior awards ceremony by his ALO in June.