Whether BC is 1, 2, or 3, it will play in Manchester unless New Hampshire is a No. 4 seed — which seems highly unlikely now. Nothing has changed in that regard. Win Hockey East, combined with a loss by North Dakota and Yale in their semifinals, and BC would be No. 1 overall. Otherwise, if UNH isn't the No. 4 seed, expect to see BC playing someone like RPI or Dartmouth in Manchester in the first round.
BC can actually drop to No. 4 overall with a loss, and with Michigan winning the CCHAs. It probably won't make much difference in placement or the bracket, though.