The 2nd coldest game was Jan. 10, 1982 at Riverfront Stadium during the AFC Championship game between Cincinnati Bengals and San Diego Chargers, at -9 deg. F, so Sundays game might take the #2 spot instead.
The deciding factor will be the timing of how fast the coldest air moves in on Sunday. The air mass is plenty cold enough to break the record, with a Monday high temperature forecast of -14 deg. F.