There is an 80/20 rule in the band saw world. 80% of machines are built with the teeth pointing one direction, while 20% are built with the teeth pointing the other. We weld all of our blades to comply with the 80%.
Thankfully, there is a simple solution. If your teeth are pointing in the wrong direction, place your hands at 9 and 3 (think of a clock). While pinching the blade between your fingers and thumbs, rotate your hands so that the blade will flip itself “inside out”. The teeth should now be pointing in the right direction.