Deploy Flask with Gunicorn but without ngix for internal API?

I have written a small Flask API and want to deploy it on an internal network (no internet access) for production use. There will only be one client system using the API during normal operation. I think the best option is to simply use Gunicorn to deploy and and call it a day, however, most articles and posts which are about "how to deploy a Flask app" use gunicorn together with nginx for the frontend. For Internet deployments this certainly makes sense but is this also the case for my usecase? Should I still add a nginx frontend?