I'm looking for the NFHS rulebook answer to this question, it slightly differs from the original scenario:
last second shot (one functioning scoreboard/team B leads Team A by 2 points/2-man crew (or 2-person if Juulie is working))
1) B1 smacks A1's arm
2) whistle
3) release
4) horn
5) ball enters basket
6) both officials know shot was released before horn but neither has definite knowledge of exact time