It's one thing to offer the same UI elements and experience, it's another thing to make it look identical in colors, spacing, fonts, icons, etc... They took it quite far imho.
Can you show some screenshots of what you mean? Gogs[0] looks plenty different from Gitlab[1] in colors, fonts, icons, and spacing. Hardly identical, but both clearly inspired from Github.
[0] http://gogs.io/imgs/screenshoots/2.png [1] https://about.gitlab.com/images/feature_page/activity_stream...