Absolutely not. They should apply the rules identically in the playoffs and SB as in the regular season. That which is against the rules in week 3 should be against the rules in week 21. They're using the same rulebook, it should be applied the same way.
And though the rule clearly states that if any part of the ball breaks the forward plane of the endzone, a touchdown results, we're talking about the Super Bowl, fer cryin' out loud. Unless a player clearly makes it all the way into the end zone, borne on the wings of angels, then it shouldn't count.
And if an offensive lineman can't hold a defender by hooking him under the arm in the Super Bowl, then what's so Super about it?