I checked the following a couple of times and if I'm wrong it can't be by much. First weekend winning teams combined 3 point shooting was 122-330 for 37%. The highest being PSU at 59% (yikes). These numbers include 5 winning teams that shot under 30% but still managed to win. Here they are and with the opponent they defeated:
Houston 25% beat N. Kentucky 15%
Princeton 16% beat AZ 19%
SD State 25% beat Charleston 21%
Tenn 25% beat Louisiana 33%
Arkansas 27% US 27%
If you remove the 5 winning teams which shot under 30%, the remaining 11 winning teams shot 103-246 for 42%.
Shooters, shooters, shooters.