Yeap, you’re ready to take off. Remember to handle multi-facing configurations (which I assumed you naturally done it to your firewall filtering in your test then 
).
The keyword is “documentation + communications”. Anything else is just continuously improved overtime.
FYI
@jarrodhroberson’s header recommendation is best to do at the stage when your API’s URI pathing is consistent and stabilized and it’s more for hardening purposes. Some good indicator would be in the past 10? releases, the changes are only related to IO data schema and no pathing changes being made.
The implementation should also be seamless as blocking API because of header can seriously traumatize your customer support center. Moreover, a lot of customers (including me) rarely poke into responded headers (you can do customer testing with curl command).