These extra module paths are specific to your production directory environment, so they can be appended in your production directory environment's environment.conf
Your $basemodulepath is specified in your puppet.conf, typically at /etc/puppetlabs/puppet/puppet.conf.
It is the value for basemodulepath in the INI format.
modulepath from the config file is not used in the directory environment according to the documentation.
More information about environment.conf: https://docs.puppet.com/puppet/4.10/config_file_environment.html
More information about appending module paths in your directory environment: https://docs.puppet.com/puppet/4.10/config_file_environment.html#modulepath