I pointed out there was no role cop, and it's safe to say Pengu wasn't one given what he said in this game's PM to everyone. Let alone, he wouldn't get a result that Robert was the PO, he simply would of gotten vanilla.
Vanilla players have role names that vary by faction; a Role Cop scanning these will get "Vanilla" as the response, again anonymising the win condition. Thus, a Mafia Goon or a Serial Killer should give the same result as a Vanilla Townie (unless they have extra abilities).
Could there be multiple cops, maybe, but more then anything I'd say there's more then likely multiple Vigs, and many universal roles. It takes vig's to win this, so I would assume there has to be many Universal backups given if there's not enough Universal backups to replace any vigs lynched/turned the game would be over in general.