How far up the all-time list Sid goes depends in large part on how many times the Pens can keep making the playoffs. This may be the last go-round with Malkin and Letang; it's difficult to fathom the Pens making the playoffs a year after losing both those guys in free agency. Sid has 3 years left on his current contract, and no one is really sure how much longer he wants to play after that; he might make the playoffs as few one or two more times after this season.
With that said, I think he's a lock to surpass Jagr before this series ends as he only needs 2 points in 3 games. If the Pens make a long-ish run of it this year, he's got a shot to pass Anderson for #4. But to catch Kurri he's going to need another postseason or two, and that's no guarantee. We are not long out from the Pens rebuilding. If Sid gets to #3 all time in spite of that, it'd certainly be a feather in his cap.