I'll preface this with unfortunately, I don't have time to look up the law and department of education guidelines in NC right now, but wanted to respond in general.
It's never "too early" to schedule an IEP meeting. It may be too early to schedule the annual meeting, but parents can request an IEP meeting at any time. Yes, it should be in writing. Also, it should not just be a request to the special education teacher (that might be construed as just requesting a "regular" meeting with a teacher). It should be a request to the entire IEP team. If the parent doesn't know the entire team members, copy the principal on the request and ask that the request to forwarded to all IEP team members.
I would also advise having her put in the request for a meeting specifics as to why she wants to change the IEP to a less restrictive environment. If she's wanting to make changes to the IEP document, she needs to have data supporting this request - even if the data is just observations of the ABA case manager, etc. However, an evaluation would hold more weight. If it has been more than a year since the last school evaluation, she can request another one because she feels her son has improved. If it hasn't been a year yet, she can request an IEE.