It's not so much the three rows as the fact that they're raised at 4 weeks. I have an araucana bantam girl with three perfect rows in her pea comb, but it's only just gotten that raised and she's 20 weeks old. Sorry for your luck - I'm having pretty much the same this year. I'll get a couple layers and a year's worth of dinners of it, though...
You keep concentrating on the comb. Now, I can't tell mine until they freaking crow, but what I have noticed is that the roo's have a comb that has the gap behind, is bigger and redder. In other words it goes back further than where it attaches to the scalp. The way I have seemed to notice is the tail feathers. If I read it on here correctly, the hens tail feathers develop faster than the rooster, since the rooster ultimately has the longer plumage.
That said, I am guessing both pullets. That and $5.00 might get you a cup of coffee at Starbucks lol!