Yea, they have quite a few that are alternating but still didn't have any preflowers. I'm pretty sure I found one today and am going to wait for it/more to develop.
If the nodes are alternating and no hairs have popped out, its 95% likely a male. It doesn't hurt to wait a bit longer. As long as you don't flip em together.
If you want 100% confirmation, you could cut a clone and get it rooted and then flip the clone. If its a male, the balls will start showing about as quickly as pistils do when you flip em....sometimes the balls show up quicker.