Well of course he knows Captain Rogers. Who doesn't? But yeah, definitely a bit more personal than just being aware of an Avenger. Still, the question is fair. He's got Steve at a real disadvantage. Which means he'll give Cap benefit of the doubt. Any Captain America that doesn't recognize the most troublesome by deliberate choice because his twin's powers are more problematic of the Young Avengers is a Captain America that hasn't wronged said troublesome almost-adult super-hero.

"Tommy Shepherd. Speed. Which is also what I do. Trying to find sufficient food for a frustratingly speedster metabolism. You're Captain America, leader of the Avengers. You know, when Stark isn't. Or when you two aren't fighting. Again."