His comb is trifid, but the entire hatch has the gene for the rough texture. Kristen Garrison has been working on her comb genetics for long enough to have worked that gene out of her flock. She's distributed birds to several members of the Society; Steampup Parlor's foundation flock is from her which is why her birds combs are smooth, too. Additionally, watermael hens seem to have a lower incidence of quality comb shape. Breeders with roosters sporting sexy combs report still struggling with quality combs in hens.
What I'm not sure of, is whether the textured comb is a fault, or a preference.
IMHO, the general shape of the comb is pretty easy to tell on the boys by week 4. You can see any little nubs that will expand with age. If you see a comb with two little nubs up top, you're gonna have two big nubs as an adult.
As an aside, my husband has decided to bond with Agate over their "maleness", or something. He claims to understand him and "we're cool, listen to him coo, he's happy". Awesome, he's your chicken now