The need of gpgkey

I am performing my installation of Kibana (full ELK stack) in my production environment now. As I am going through the documentation I see that when installing it indicates the need to add the lines :

baseurl=https://artifacts.elastic.co/packages/7.x/yum

gpgkey=https://artifacts.elastic.co/GPG-KEY-ElasticSearch.

My question is as follows. I am working in an self-contained environment that does not have internet access, and subsequently is not able to access the elastic.co website. I have downloaded all the install files and had them uploaded to the RHEL 8.0 servers, and am working with ELK 7.13.4. Do I need to add the above lines that reference the elastic website? Do I need the GPGKEY?

Thank you for your assistance with this.

If you've downloaded all the RPMs, then no, you don't need to add that to your packages sources.