While we may not get to see Rob play guitar in Remember Me (we can always wish) - Summit has released some details of what's included on the DVD & Blu-ray:
-- Audio Commentary with Robert Pattinson and cast
-- Audio Commentary with Director Allen Coulter
-- Making Of featurette
Of course, Rob had already spilled the beans when he talked to @colliderfrosty during the Remember Me promo (at about 2:38).
We will update you as we get more details! - The Remember Me DVD & Blu-ray will be released June 22.