I bought this gal/guy hoping for a hen, but I have a feeling - with the streamers - it's a rooster. Personality wise, he's the lowest in the flock and the other rooster (very obvious a rooster) picks at him. He's very docile.
Silkies are hard and I'm far from an expert, but I would say your guess of a roo is probably accurate.
My silkie roo looked just like that with the "hair" pointed back versus the hen pouf ball.
But they can be tricky so I wouldn't give up just in case!