Without using an App-id
- you can't integrate these facebook social plugins.
The developer can use his own account for the app creation, then any time later he can add/remove administrator. So, before submitting to the client, just add the client as admin and remove yourself as the admin. See here how to do it-
But of course the client must have verified his/her account, else you'll not be able to add -
But dont worry not a big deal, just tell your client to go here and verify the account. Simple enough?