i would say pullet. i have found all my silkies to show their sex no later than 3 months. Now, that may be because i don't have show quality silkies, just pretty lawn ornaments. But i would think you would see bigger wattles or a large comb by this age.
I'm saying cockerel....... his color almost looks silver laced .... even though I know this is not a Silkie color.... it has that look about it. Can you get a pic of the wing feathers?? Just to satisfy my own curiosity
I'll take some better pics today. I attempted to groom "him" as Poulets suggested, so "he" does look a little better...but I'm not exactly a pro at chicken grooming, either!