Silver Sox is definitely a [spoiler], right?

Finally finished Romeo is a Deadman last night, and Silver Sox is definitely a Sumio Mondo, right? He dresses identically to them and his face looks pretty similar, the only difference being his haircut. He jacks into people through the eye, he talks about shared memories and questions his own, so on and so forth. Hell, he's the one guy whose color-inspired name is Silver.

Assuming he is, I do wonder if he's part of Sumio Kodai's consciousness and is the "real" Sumio, or if he's like Sundance Shot and is a clone with his own sentience