It is difficult to say what an auditor would do, just as it is difficult to say what a coder would do, because roles and guidelines vary by organization, as do their relationships with payers and tolerances for risk. A strict auditor would cite it as an error and take back the overpayment, but in my experience, payers audit E&M codes to look for trends of abuse and chronic up-coding that add up to a lot of money, not to find $30 here and there by challenging minor details in how the provider worded their documentation. I really doubt that a auditor would find fault with this as they're usually looking mainly to see if the level is supported by the patient's problems and they don't want to generate appeals, but you never know.
But again, I'd refer you back to your organization and what your role is. If your job is to choose the code or to correct the provider's code, then you should follow your guidelines and pick the appropriate code based on your training. If your job is to validate what the provider has chosen, then your practice should be the one to tell you what steps you need to take when you identify a variance between your code and the provider's. But in either case, in that situation myself, I would not submit a query or request an addendum for something of this magnitude - the amount of time it will take you and the provider will likely exceed the value of the difference in reimbursement between the levels.