Hi Kevin80,
The NAICS Code is a classification business code used for statistical purposes only. Based on the information you provided in your question, it seems that your business has slightly transitioned over the years based on customer demand and business model. If everything else is the same (organization type, reporting under the same Social Security or EIN number), you can simply update your NAICS code on your next tax return filing. This will not have an impact on your tax return.
For your convenience, here is a helpful link to confirm the information I provided to you above.
https://ttlc.intuit.com/community/business/help/what-is-the-business-code-used-for/00/25672