SAN FRANCISCO — NaVorro Bowman and Patrick Willis will harass the quarterback. The defense will probably force a turnover. Frank Gore will run for around 100 yards and Alex Smith will protect the ball. Everybody pretty much knows what to expect from the San Francisco 49ers by now. That’s hardly the case with the Buffalo Bills. Piling up points one minute, handing them out the next, what Bills (2-2) team travels to the West Coast to face the 49ers (3-1) on Sunday is anybody’s guess. After allowing 45 second-half points in an embarrassing 52-28 home loss to New England last …