By default, emails exported by the tool are not original because Google's anti-spam mechanism removes some characters from them, for e.g,
this.is.my.email@example.net --> this.....@example.net
The discourse has a great script to fix this problem, as seen at
This script was imported to the google-group-crawler project, but it
was removed on Apr 24th 2017 due to license problem as described here
Removing is the best way to avoid duplication and future confusion.