Hi. In the modern world nothing is sent and nothing is printed on a dot matrix printer

All the crap is in the cloud and in the online system that AdCom can access and look up. They will not turn to the LOR's until It is time to review your application. Same is with the GMAT Scores, they won't be verifying them until after the deadline sometime and looking them up in the database.
As to the LOR's - I know you can change recommenders but I don't know if you can add one, remove them and then add them again. This may depend on which Application system is used such as ApplyWeb or the other one. One idea: you can play around with it using a dummy application account and send yourself an invitiation using another email address of yours an LOR request, fill it out then log back into a dummy account, delete it and see if you can add the same email to the system. My only concern is being able to add the same email twice.
There are no concerns with the AdCom seeing that your recommender fumbled (it is a bit of an odd thing that they submitted it since it asks you and gives you a warning AFTER you click submit that says, you sure you want to submit and they have to confirm it again). However, no reason to be harsh on recommenders. It is a hard job writing LOR's and you should be graceful and forgiving to them. Anyway, recommenders mess up all the time. It is not unusual

Anyway, you can experiment with a dummy account and get your answer that way.
-BB