I can’t confirm this. The link to the relevant IMDb page is contained in the column ‘MetaDB Link’ This link has the IMDb ID of the movie.
That’s about everything IMDb-related you can get from the Plex database.
And it will only work if the movie has been matched with the ‘Plex Movie’ agent.
If you have been using TheMoviedatabase, all you’ll get is the link to the record on the TMDB.
Switching the primary metadata agent of your library afterwards won’t change this. The metadata agent is linked to the movie record in the Plex DB and won’t change unless you remove the movie and add it ‘as new’ (e.g. after performing the Plex Dance or deleting the whole library and re-creating it.)