Of course it might not last. But if he performs 82 games at this level, absolutely it's Selke-level stuff.
Pettersson has been absolutely horrible defensively this year, by contrast. I agree that he's 'naturally' the better player but one guy is willing himself to excellence and the other is injured or floating.
I don't think they really handicap the Selke by saying he's playing with generally average, to below-average, defensive linemates. Even if he is to a degree making chicken salad out of chicken shit. You can certainly make the case he's the best Selke candidate on the Canucks, but nobody on the team should really be in the conversation alongside the league's elite defensive players given the stats. Even if your eyes are telling you something else.
And if you want to bring up linemates you also have to bring up the strength of schedule and the Canucks have not had a challenging one to date, though they do have one of, if not the most, difficult remaining schedules in the Pacific .... so we're certainly going to see if it lasts.