How to make sure all the config files are correct before deploying to the production environment?

I have a spring 3 application running on AWS Elastic Beanstalk. Before I deploy the application to the production environment, I run a script to modify some of the parameters (e.g., database URL, website URL, AWS region, ...) so that it can run correctly on the environment.

How can I make sure that these parameters are correct before deploying to the production environment?

I think I can run a smoke test immediately after the deployment. But if something goes wrong with the config files, I'll still create a short down time for the production environment.