There is an issue for gitlab-ce (Community Edition) concerning Access Control for gitlab pages:
As of February 2018, this is not closed yet, but it doesn’t mean it’s “not possible”.
1. Gitlab pages behind your own private gitlab installation:
If you are using your own gitlab installation (not gitlab.com), and your gitlab installation is in a private network only accessible with a vpn, then only users behind that vpn will have access to your generated gitlab-pages.
2. Publish to a private server:
Another solution using gitlab.com would be to deploy your website somewhere online using gitlab-ci and use your own authentication system. Or you can upload generated content to a private AWS S3 bucket. Here’s an example of how to setup a S3 bucket with Authentication
The following guide will show you how to use gitlab-ci and the
awscli to deploy your html files to AWS S3:
So in the end, I don’t think answering “No” is the right answer here.